PATH Study Interim Report

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Population Assessment of Tobacco and Health (PATH) Study (NIDA)

PATH Study Interim Report

OMB: 0925-0664

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Population Assessment of Tobacco and Health (PATH) Study (NIDA)

Attachment 21
PATH Study
Interim Report on Baseline Data
and Biospecimen Collection
June 26, 2014

Population Assessment of
Tobacco and Health Study
Interim Report to the Office of
Management and Budget on
Baseline Data and Biospecimen
Collection

April 28, 2014

Submitted by:
Kevin P. Conway, Ph.D.
Deputy Director
Division of Epidemiology, Services, and Prevention Research
National Institute on Drug Abuse
6001 Executive Blvd., Room 5185
Rockville, MD 20852
Phone: 301-443-8755
Email: PATHprojectofficer@mail.nih.gov

Table of Contents

Section
1

Page
Introduction ........................................................................................................

1.1
1.2

Overview of Sample Design for Baseline Wave...............................
Predictor Sample ...................................................................................

2
3

Response Rates Associated with the Household Screener ...........................

2.1
2.2

Method ...................................................................................................
Results .....................................................................................................

5
7

Response Rates Associated with the Adult and Youth Interviews .............

3.1
3.2

Adult Extended Interview ...................................................................
Youth Interview ....................................................................................

9
12

Response Rates Associated with the Biospecimen Collections ...................

4.1
4.2

14
16

Nonresponse Bias Analysis ...............................................................................

5.1
5.2

17
20

Statistical Approach for Addressing Nonresponse........................................

6.1
6.2

Computation of Nonresponse-Adjusted Weights ...........................
Results .....................................................................................................

33
36

Discussion ............................................................................................................

7.1
7.2

Summary of Findings ...........................................................................
Conclusions and Implications for Study Going Forward ...............

46
49

References ............................................................................................................

iii

Contents (continued)

Appendix
A

Page
Cigarette Smoking Questions on the PATH Study and Other
Surveys .................................................................................................................

A-1

PATH Study baseline predicted response rates for the predictor
sample, by address characteristics: Household Screener ..............................

3-1

PATH Study baseline predicted response rates for the predictor
sample, by respondent characteristics: Adult Extended Interview .............

3-2

PATH Study baseline predicted response rates for the predictor
sample, by respondent characteristics: Youth Interview ..............................

4-1

PATH Study baseline predicted response rates for the predictor
sample, by respondent characteristics: Biospecimen collections .................

5-1

Race by age distribution, based on the household enumeration .................

5-2

Distribution of male and female adults listed in the household
enumeration .........................................................................................................

5-3

Distribution of household size based on households responding
to the Household Screener ................................................................................

5-4

Distribution of number of adults based on households
responding to the Household Screener ...........................................................

5-5

Distribution of number of youth ages 12-17 based on households
responding to the Household Screener ...........................................................

5-6

Demographic distributions based on adults responding to the
Adult Extended Interview, and on adults from whom urine,
buccal, and/or blood specimens were collected ............................................

Comparison of education level and health insurance status based
on adults responding to the Adult Extended Interview, and on
adults from whom urine, buccal, and/or blood specimens were
collected ...............................................................................................................

Table
2-1

5-7

Contents (continued)

Table
5-8

Page
Current cigarette smoking based on adults responding to the
Adult Extended Interview .................................................................................

5-9

Current cigarette smoking based on adults from whom
biospecimens were collected .............................................................................

5-10

Demographic distributions based on youth ages 12-17 who
completed the Youth Interview ........................................................................

5-11

Cigarette smoking based on youth ages 12-17 who completed the
Youth Interview ..................................................................................................

6-1

Race by age distribution, based on household enumeration ........................

6-2

Distribution of male and female adults listed in the household
enumeration .........................................................................................................

6-3

Distribution of household size based on households responding
to the Household Screener ................................................................................

6-4

Distribution of number of adults based on households
responding to the Household Screener ...........................................................

6-5

Distribution of number of youth ages 12-17 based on households
responding to the Household Screener ...........................................................

6-6

Comparison of education level and health insurance status based
on adults responding to the Adult Extended Interview, and on
adults from whom urine, buccal, and/or blood specimens were
collected ...............................................................................................................

6-8

Current cigarette smoking based on adults responding to the
Adult Extended Interview .................................................................................

6-9

Current cigarette smoking based on adults from whom
biospecimens were collected .............................................................................

6-7

Contents (continued)

Table
6-10

Page
Demographic distributions based on youth ages 12-17 who
completed the Youth Interview ........................................................................

6-11

Cigarette smoking* based on youth ages 12-17 who completed
the Youth Interview ...........................................................................................

7-1

Summary of PATH Study baseline overall response rates for the
predictor sample .................................................................................................

A-1.

Question used to define “current smoking” in the PATH Study,
TUS-CPS, NHIS, NHANES, and NSDUH ..................................................

A-2

A-2.

Questions used for youth cigarette smoking in the PATH Study,
NHANES, NSDUH, and NYTS .....................................................................

A-4

Schematic of the PATH Study sample design with counts for the
predictor sample .................................................................................................

Figure
1-1

Introduction

The Population Assessment of Tobacco and Health (PATH) Study is in the midst of completing the
baseline wave of its planned 3-year data and biospecimen collection effort. The Office of
Management and Budget (OMB) approved the PATH Study’s non-substantive change request for
the baseline wave collection on August 23, 2013 (0925-0664). The terms of clearance of OMB's
approval state: “Before submitting the second wave of data collection to OMB for approval under
the PRA (Paperwork Reduction Act), NIDA/FDA should report to OMB regarding the response
rates associated with the baseline (screening, interview completion, and bio-specimen response), the
results of nonresponse analysis, the statistical approach for addressing nonresponse, and the
implications for the study going forward.”
This report is submitted by NIDA/FDA to meet OMB's terms of clearance. The contents are
presented as specified in the terms of clearance: Sections 2, 3, and 4 present the response rates;
Section 5 provides the results of a nonresponse analysis; Section 6 discusses the statistical approach
for addressing nonresponse; and Section 7 summarizes the findings and considers their implications.
The rates provided in this report are for the “predictor sample,” the probability sample of addresses
selected for the main study that were released to field interviewers early in the field period as the first
priority of field work. These rates for the predictor sample are compared throughout this report to
corresponding rates projected for the best-case and worst-case scenarios for the entire sample,
provided in “Attachment 22.” (“Attachment 22” is part of Supporting Statement B of the PATH
Study's non-substantive change request for the baseline wave of data and biospecimen collection.)
The report covers approximately 5 months of the PATH Study's 12-month baseline, from
September 12, 2013 to February 26, 2014, and the analyses are performed on data collected in a
subsample of the full study sample called the predictor sample.
The next section provides an overview of the sample design for the PATH Study baseline wave and
a description of the predictor sample on which this interim report is based. Information on the study
background and overall design is provided in Supporting Statement A of the PATH Study's nonsubstantive change request for the baseline wave.

Population Assessment of Tobacco and Health Study

1.1

Overview of Sample Design for Baseline Wave

The target population of the PATH Study is the civilian, non-institutionalized U.S. population
(excluding Puerto Rico) 12 years of age and older. Active duty military personnel and residents of
group quarters are also excluded, with the exception of college students. A four-stage stratified area
probability sample design is used, with a two-phase design for sampling the adult cohort at the final
stage. The sampling rates for adults vary by age, race, and tobacco use status. At the first stage, a
stratified sample of geographical primary sampling units (PSUs) was selected, in which a PSU is a
county or group of counties. For the second stage, within each selected PSU, smaller geographical
segments were formed and then a sample of these segments was drawn. At the third stage, the
sampling frame consists of the residential addresses in the U.S. The main source of these addresses
is the Postal Service (USPS) Computerized Delivery Sequence Files (CDSFs).
The fourth stage selects persons from the sampled households. A roster of all the members in the
sampled household is constructed by interviewing one adult household member (referred to as the
household informant) to list the members and collect some information about each one for use in
sampling the three groups of interest:


Adults (up to two adults per household);



Children ages 12 to 17 (referred to as “youth,” generally up to two per household); and



Children ages 9 to 11 (referred to as “shadow youth,” generally up to two per
household) to be enrolled in the youth cohort in later waves of the study on reaching 12
years of age.

Given the possible misreporting of tobacco use status of each adult in the household by the
household informant, two-phase sampling is used for adult selection. The Phase 1 sampling depends
on the age, race, and tobacco use information provided by the household informant. The Phase 2
sampling is based on the self-reported age, race, and tobacco use status, obtained by interviewing the
individuals sampled at the first phase. The sampling rates for the two phases are designed to achieve
large enough sample sizes for young adults (ages 18 to 24) and adult tobacco users of all ages. The
tobacco use status reported by the household informant is referred to as “Phase 1 tobacco use
status.” The self-reported tobacco use information obtained during Phase 2 screening is referred to
as “Phase 2 tobacco use status.”
Because the full sample is selected using probability sampling methods, it is representative of the
U.S. civilian non-institutionalized population 12 years of age and older.

Population Assessment of Tobacco and Health Study

1.2

Predictor Sample

Figure 1-1 is a graphic presentation of the sample design. It presents counts for the sampling
stages/phases and data collection outcomes for the predictor sample. The PATH Study baseline
sample was divided into four replicate groups, consisting of probability samples of approximately 20
percent, 30 percent, 30 percent, and 20 percent of the sampled segments, respectively, within each
sampled primary sampling unit (PSU). Each separate replicate group is therefore also representative
of the civilian non-institutionalized U.S. population, because it is a probability sample from the set
of segments in the frame. The data collection plan calls for the release of replicate groups to the
field in a sequential manner (i.e., replicate group 1 in September 2013, replicate group 2 in
November 2013, replicate group 3 in February 2014, and replicate group 4 in May 2014).
A random sample of segments selected from each PSU in replicate group 1, where is the nearest
integer to (3/8) x (number of segments in the PSU), was designated as the predictor sample. Because
the predictor sample is a randomly selected subsample of the full sample, it is also approximately
representative1 of the civilian non-institutionalized U.S. population. Those segments were assigned
early in the field period so that preliminary estimates from the predictor sample would be available
to inform the response rates and nonresponse analysis in this report. The predictor sample consists
of 455 segments selected from the 1,220 segments in replicate group 1, with representation from all
156 PSUs in the PATH Study sample; this sample includes 11,799 addresses, of which 10,590
addresses were eligible.
Weighting is discussed briefly in Sections 2.1, 3.1, and 4.1. More detailed information on it is
provided in Sections 5 and 6.

Some segments had incomplete information about addresses from the USPS CDSFs, and field staff listed the addresses
in these segments using traditional, on-the-ground, in-person listing methods. The segments that were listed were not
given a chance of selection for the predictor sample, because the extra time required for listing meant that survey data
from such segments was not available within the required timeframe. A total of 59 out of the 1,220 segments in
replicate group 1 were selected for listing. Similarly, the predictor sample addresses did not include addresses added to
the sample as a result of the address verification (AV) procedure. The AV procedure was performed on a probability
sample of the non-listed segments to ensure complete coverage for the PATH Study. In each segment selected for the
AV procedure, field interviewers canvassed the segment and listed addresses not on the USPS CDSFs for potential
inclusion in the sample, along with the addresses selected from the CDSF. The small number of additional listed
addresses from the 50 predictor sample segments undergoing the AV procedure were not available in time to be
included in the predictor sample. The predictor sample therefore does not have representation from the listed
segments or addresses not found on the USPS CDSFs.

Population Assessment of Tobacco and Health Study

Figure 1-1.

Schematic of the PATH Study sample design with counts for the predictor sample

PSU sample
(156 PSUs)

Segment
sample (6049
segments)

Segment
samples for
replicates 2 to 4
(4,829
segments)

Replicate 1
segment sample
(1,220
segments)
Predictor
sample
segments
(455
segments)

Balance of
Replicate 1
segments
(765
segments)

Address
sample
(11,799
addresses)
Occupied,
residential
addresses
(eligible
households)
(n=10,590)

Final household
screener
nonresponse
(n=3,537)

Completed
Household
(Phase 1)
Screeners
(n=5,655)

Phase 1 adult
sample
(n=3,894)

Interim household
screeners
(n=1,398)
Apportioned by modeling:
404 likely to be completed
994 likely nonresponse

Final Youth
Extended Interview
nonresponse
( n=106)

Interim Phase 2 screeners
(n=475)
Apportioned by modeling:
169 likely to be completed
306 likely nonresponse

Final Phase 2
Screener
nonresponse
(n = 599)

Adults not sampled
for PATH
(n=821)

Completed
Phase 2
Screeners
(n=2,820)

Final Adult
Extended Interview
nonresponse
(n=8)

Adults sampled
for PATH
(n=1,999)

Completed
Youth Extended
Interviews
(n=964)

Youth sampled
for PATH
(n=1,265)

Interim Youth Extended
Interviews
(n=195)
Apportioned by
modeling:
59 likely to be completed
136 likely nonresponse
Buccal cell
specimens
collected
(n=1,408)
Completed
Adult Extended
Interviews
(n=1,991)

Urine
specimens
collected
(n=1,253)
Blood
specimens
collected
(n=734)

Population Assessment of Tobacco and Health Study

Response Rates Associated with the Household
Screener

The baseline Household Screener (also referred to as “Phase 1” in Section 5) combines typical
screener functions (e.g., enumerating the household, collecting basic demographic information about
each member, collecting some household-level data, and selecting participants for the study) with a
special purpose for the PATH Study, which is to collect minimum information on each adult’s
tobacco use. This allows for classifying the adult with sufficient validity for potential selection as a
participant based on the PATH Study’s sampling strata on tobacco use and demographic
characteristics. Field interviewers conduct the Household Screener in person using computerassisted personal interviewing (CAPI).

2.1

Method

As of February 26, 2014, 9,192 (86.8%) Household Screener cases were finalized, and 1,398 (13.2%)
cases were still being followed up in field work.
Response rates presented in this report were computed in a manner consistent with the response
rate formula specified by OMB in its “Standards and Guidelines for Statistical Surveys” (2006). This
formula calls for calculating unweighted unit response rates (RRU) as the ratio of the number of
completed cases (or sufficient partials) to the number of in-scope sample cases.2 The different
categories of cases that comprise the total number of in-scope cases are defined as follows:
C
R
NC
O
U
e

=
=
=
=
=
=

number of completed cases or sufficient partials;
number of refused cases;
number of noncontacted sample units known to be eligible;
number of eligible sample units not responding for reasons other than refusal;
number of sample units of unknown eligibility, not completed; and
estimated proportion of sample units of unknown eligibility that are eligible.

The unweighted unit response rate represents a composite of these components:
RRU=C/(C+R+NC+O+e(U))
2

The predictor sample does not have any partial completes.

Population Assessment of Tobacco and Health Study

This response rate formula applies most directly to data collections that have been completed.
Because the PATH Study baseline data and biospecimen collection is ongoing, however, the formula
must consider nonfinalized or interim status cases as well as finalized cases; in this sense, the
response rates presented in the interim report are “predicted.” Hence, the unweighted unit response
rates used for this interim report are as follows:
RRU = ((C+(X * IR)+(Y * IO))/(C+R+NC+O+1(U)+IR+IO), where additionally
IR
IO
X
Y

=
=
=
=

number of ever refused interim cases;
number of never refused interim cases;
probability of IR cases becoming respondents; and
probability of IO cases becoming respondents.

For this report, the PATH Study modeled the probabilities of interim cases becoming respondents,
X and Y, using a procedure to project outcomes in biostatistics.3 The mean probabilities of the
interim cases are 0.11 for households that have ever refused, and 0.47 for the households that have
never refused. These probabilities are consistent with the resolution rates found for interim cases
based on number of call attempts by Wang et al. (2005). Note that the predicted response rates
assume all pending cases are eligible (i.e., e = 1).
Table 2-1 provides overall predicted response rates for the Household Screener and response rates
for subgroups of sampled households that belong to Census block groups with various
characteristics. After the characteristic column, the table includes columns on the number of
completed cases, number of interim cases likely to become respondents, number of finalized
nonresponse cases, number of total interim cases, unweighted response rates, and weighted response
rates. The response rates were weighted to compensate for unequal probabilities of selection due to
planned oversampling of individuals with certain characteristics (i.e., young adults, African-American
adults, and adult tobacco users). Without weighting, the response rates would be expected to be
biased. The Household Screener inverse probability of selection (IPS) weights were calculated as the
inverse of the selection probabilities for all households sampled (responding households and
nonresponding households).(See Section 5.1 for additional information on weighting.)
3

The procedure entailed two steps. First, interim cases were divided into two categories: households that had refused
one or more times (households that had ever refused), and households that had never refused. Second, for each
category, a cumulative incidence model (Gooley et al., 1999) was fit to finalized cases. This model was used to estimate
the probability that an interim case would become a respondent within 15 contact attempts as a function of the
number of contact attempts to date. For the purpose of modeling the predictor sample, the results indicated up to 15
contact attempts captured the effects of the majority of field effort while still providing sufficient sample size of
finalized cases from which to estimate probabilities of completion.

Population Assessment of Tobacco and Health Study

In addition to the overall row, the table includes rows on education, race, ethnicity, and poverty
status subgroups. For example, the weighted response rate for addresses in Census block groups
with “high” levels of education (>29.1% of persons ages 25 and older with Bachelor’s degrees) was
51.9 percent; it was 60.8 percent for addresses in Census block groups with “low” levels of
education. Comparing subgroups of responding and nonresponding households on response rates
informs an assessment of the extent to which the responding addresses represent all sampled
addresses and, ultimately, the population of inference. To include information on the characteristics
of both respondents and nonrespondents, subgroups are defined by the characteristics of the
Census block groups in which the sampled addresses are located; this information is from the 5-year
(2008 to 2012) American Community Survey (ACS).4 The “high” and “low” subgroup categories
were defined relative to the nationwide percentage of persons having the characteristic: block groups
whose percentages were below the national average for the characteristic were classified as low and
those whose percentages were above the national average were classified as high. The cases with
missing values for a given characteristic were excluded from the response rate calculation for that
characteristic.

2.2

Results

As indicated in Table 2-1, the weighted overall predicted response rate for the Household Screener
is 57.1 percent. The weighted response rates for demographic subgroups indicate the subgroups
differ from one another by as much as 8.9 percentage points. The differences among subgroups on
weighted response rates were 8.9 percentage points for education, 2.6 percentage points for race, 3.8
percentage points for ethnicity, and 8.7 percentage points for poverty status. The overall predicted
response rate for the Household Screener is lower than the projected rate of 70 percent previously
presented to OMB in Attachment 22, but it exceeds the worst-case scenario response rate of 39.7
percent.

Information from the 5-year (2008 to 2012) rather than the 1-year (2012) ACS was used because 1-year ACS estimates
are not provided for smaller geographies such as Census tracts or block groups. The 5-year ACS estimates, which are
based on the accumulated sample from 2008 to 2012, are the only estimates from ACS that can provide information at
the tract level and smaller geographies (see http://www.census.gov/acs/www/guidance_for_data_users/estimates/).

Table 2-1.

PATH Study baseline predicted response rates for the predictor sample, by address characteristics: Household Screener

B
C
Interim likely to
Finalized
be completedb nonresponsec
(n)
(n)
404
3,537

D
Total
interimd
(n)
1,398

Weighted
predicted response
rate for baseline,
based on
predictor samplee
(%)
57.1

2,118
3,537

159
245

1,707
1,830

566
832

51.9
61.0

51.9
60.8

1,360
4,295

74
330

991
2,546

231
1,167

55.5
57.8

55.1
57.7

1,473
4,182

132
272

786
2,751

421
977

59.9
56.3

59.9
56.1

2,159
3,496

146
258

1,032
2,505

467
931

63.0
54.2

62.8
54.1

Note: The projected response rate for baseline is 70 percent.
a

The characteristics are as sampled. That is, information on the characteristics was collected in the Household Screener. The information used to define the subgroups is from the 5-year
(2008 to 2012) American Community Survey.

Interim likely to be completed is the sum of : (1) the product of the number of ever refused interim cases and the estimated proportion of ever refused interim cases that will ultimately
result in completes, and (2) the product of the number of never refused interim cases and the estimated proportion of never refused interim cases that will ultimately result in completes.

Finalized nonresponse includes refused cases and all other nonresponding cases.

Total interim includes ever refused interim cases and never refused interim cases.

Predicted response rate = (A+B)/(A+C+D).

Population Assessment of Tobacco and Health Study

Characteristica
Overall
Education (% with Bachelor’s degree)
High > 29.1%
Low <= 29.1%
Race (% Black alone or in combination)
High > 13.7%
Low <= 13.7%
Ethnicity (% Hispanic)
High > 16.9%
Low <= 16.9%
Poverty Status
High > 15.9%
Low <= 15.9%

A
Completed
(n)
5,655

Unweighted
predicted response
rate for baseline,
based on
predictor samplee
(%)
57.2

Population Assessment of Tobacco and Health Study

Response Rates Associated with the
Adult and Youth Interviews
3.1

Adult Extended Interview

The Adult Extended Interview gathers information from adults (18 years old and older) about
tobacco use behaviors, attitudes, knowledge, and health effects, as well as other information
including demographics, environmental factors, family and peer influences, substance use, and
general physical and mental health status. Field interviewers conducted the Adult Extended
Interviews in person using audio computer-assisted self-interviewing (ACASI).

Method
The predictor sample includes 1,999 adults selected for the Adult Extended Interview. As of
February 26, 2014, all of the Adult Extended Interview cases were finalized.
Table 3-1 provides overall predicted response rates for the Adult Extended Interview and response
rates for tobacco use status5 and demographic subgroups. All response rates are conditional on a
completed Household Screener. The response rates were calculated as the product of (1) the
Individual or Phase 2 Screener6 response rate (which uses the same formula as the Household
Screener); and (2) the proportion of adults who completed the Adult Extended Interview among
those who completed the Phase 2 Screener and were selected for the Adult Extended Interview:
RRU = (((C+(X * IR)+(Y * IO))/(C+R+NC+O+1(U)+IR+IO))*(CE/(CE+CX)), where
IR
IO
X
Y

=
=
=
=

number of ever refused interim cases;
number of never refused interim cases;
probability of IR cases becoming respondents;
probability of IO cases becoming respondents;

Tobacco use status is as sampled based on information obtained in the Household Screener.

Adults selected on the basis of the Household Screener were asked to complete the Phase 2 Screener. Those who
completed the Phase 2 Screener were eligible for selection for the Adult Extended Interview, subject to further
subsampling to achieve the design targets for the various age, race, and tobacco use groups. Of the adults who
completed the Phase 2 Screener and were selected for the Adult Extended Interview, approximately 99.6 percent
completed the Adult Extended Interview.

Population Assessment of Tobacco and Health Study

CE = number of Adult Extended Interview completes; and
CX = number of Adult Extended Interview nonresponses.
For this report, the PATH Study modeled the probabilities of interim cases becoming respondents,
X and Y, using the procedure described in Section 2.1. The mean probabilities of the interim cases
are 0.07 for adults who ever refused, and 0.57 for the adults who never refused. Again, the predicted
response rates assume all pending cases are eligible.
The adult response rates were weighted to compensate for unequal probabilities of selection due to
planned oversampling of individuals with certain characteristics. Person-level weights for adults are
the product of the Household Screener IPS weights and individual adult IPS weights, which were
calculated as the inverse of the selection probabilities for all adults sampled (responding adults and
nonresponding adults). (See Section 5.1 for additional information on weighting.)
In addition to the overall row, the table includes rows on tobacco use status, age, sex, race, and
ethnicity subgroups. Information from the Household Screener is used to define the demographic
characteristics for the responding and nonresponding adults. Some adults had missing values for
these characteristics on the Household Screener. Adults with missing information about tobacco use
status were sampled using the selection probabilities associated with tobacco users, and are included
in the “sampled as user” row of Table 3-1. The cases with missing values for other characteristics
were excluded from the response rate calculation for that characteristic.

Results
As indicated in Table 3-1, the weighted overall predicted response rate for the Adult Extended
Interview is 75.7 percent. This overall rate is lower than the projected rate of 85 percent, but it
exceeds the worst-case scenario response rate of 58.1 percent previously provided to OMB in
Attachment 22.
The findings on the weighted response rates for tobacco use status and demographic subgroups
indicate the subgroups differ from one another by as much as 8.5 percentage points. As noted,
information on the tobacco use status and demographic characteristics of eligible participants used
in this table was gathered in the Household Screener. The differences among subgroups on weighted
response rates were 1.3 percentage points for tobacco use status, 5.2 percentage points for age, 1.7
percentage points for sex, 8.5 percentage point for race, and 2.6 percentage points for ethnicity.

Population Assessment of Tobacco and Health Study

Table 3-1.

PATH Study baseline predicted response rates for the predictor sample, by respondent characteristics: Adult Extended Interview
Phase 2 Screener

Characteristica

C
P2 Screener,
finalized
nonresponsec
(n)

D
P2
Screener,
total
interimd
(n)

F
E
Adult Extended,
Adult Extended,
finalized
completed
nonresponse
(n)
(n)

Unweighted
predicted
response rate
for baseline,
based on
predictor
samplee
(%)

Weighted
predicted
response rate
for baseline,
based on
predictor
samplee
(%)

2,820

169

599

475

1,991

76.5

75.7

1,473
1,347

88
82

307
292

243
232

1,301
690

2
6

77.0
75.7

77.2
74.8

733
967
764
339

48
65
41
11

145
173
176
91

122
171
132
40

516
748
524
195

2
3
3

78.1
78.5
74.6
73.3

77.8
78.4
74.1
72.3

1,396
1,424

95
72

304
288

258
213

1,040
951

5
3

75.8
77.5

75.4
76.2

2,056

125

443

358

1,482

76.0

75.4

464
221

24
13

77
61

58
38

306
164

1
1

81.1
72.6

80.2
72.1

491
2,327

48
118

69
522

115
352

333
1,656

4
4

78.8
76.2

76.8
75.6

Note: The projected response rate for baseline is 85 percent.
a
b

c
d
e
f

The characteristics are as sampled. That is, information on the characteristics was collected in the Household Screener.
Interim likely to be completed is the sum of: (1) the product of the number of ever refused interim cases and the estimated proportion of ever refused interim cases that will ultimately result in
completes, and (2) the product of the number of never refused interim cases and the estimated proportion of never refused interim cases that will ultimately result in completes.
Finalized nonresponse includes refused cases and all other nonresponding cases.
Total interim includes ever refused interim cases and never refused interim cases.
Predicted response rate = ((A+B)/(A+C+D))*(E/(E+F)).
The sum of counts for this category do not sum to the overall total due to missing values. The number of missing cases is 8 for age, 39 for race, and 2 for ethnicity.

Population Assessment of Tobacco and Health Study

Overall
Tobacco use status
Sampled as user
Sampled as non-user
Agef
18-24
25-44
45-64
65+
Sex
Male
Female
Racef
White only
Black only or in combination
with some other race
Other
Ethnicityf
Hispanic
Non-Hispanic

A
P2 Screener,
completed
(n)

B
P2 Screener,
interim likely
to be
completedb
(n)

Adult Extended Interview

Population Assessment of Tobacco and Health Study

3.2

Youth Interview

The Youth Interview gathers information from youth (12 to 17 years old) on similar topics as those
in the Adult Extended Interview. Sampled youth are asked about their tobacco use and attitudes
about tobacco. In addition, demographic information is collected and youth are asked about
environmental factors, family and peer influences, substance use, and mental health. Field
interviewers conducted the interviews in person using ACASI.

Method
The predictor sample includes 1,265 youth selected for the Youth Interview. As of February 26,
2014, 1,070 (84.6%) Youth Interview cases were finalized, and 195 (15.4%) cases were still being
followed up in field work.
Table 3-2 provides overall predicted response rates for the Youth Interview and responses rates for
demographic subgroups. All response rates are conditional on a completed Household Screener.
The response rates were calculated using the same formula as that for the Adult Extended Interview.
The same probability of never refused interim cases becoming respondents (0.57) and ever refused
interim cases becoming respondents (0.07) were used for the Adult Extended Interview and Youth
Interview. (See Section 3.1.)
The youth response rates were weighted to compensate for unequal probabilities of selection due to
subsampling of youth in households with more than two youths. Person-level weights for youth are
the product of the Household Screener IPS weights and individual youth IPS weights, which were
calculated as the inverse of the selection probabilities for all youth sampled (responding youth and
nonresponding youth). (See Section 5.1 for additional information on weighting.)
In addition to the overall row, the table includes rows on age, sex, race, and ethnicity subgroups.
Information from the Household Screener is used to define the demographic characteristics for the
responding and nonresponding youth. Because the PATH Study did not collect information on the
tobacco use of youth in the Household Screener, information on response rates for that
characteristic is unavailable. Youth with missing values for some of the characteristics on the
Household Screener were excluded from the response rate calculation for that characteristic.

Population Assessment of Tobacco and Health Study

Results
As indicated in Table 3-2, the weighted overall predicted response rate for the Youth Interview is
81.2 percent. This overall rate is higher than the projected rate of 75 percent in Attachment 22. A
worst-case scenario response rate was not specified for the Youth Interview.
The findings on the weighted response rates for demographic subgroups indicate the subgroups
differ from one another by as much as 6.1 percentage points. Information on the demographic
characteristics of eligible participants used in this table was gathered in the Household Screener.
Differences among subgroups on weighted response rates were 4.1 percentage points for age, 1.3
percentage points for sex, 6.1 percentage point for race, and 3.6 percentage points for ethnicity.
Table 3-2.

PATH Study baseline predicted response rates for the predictor sample, by
respondent characteristics: Youth Interview

Characteristica

Overall
Agef
12-14
15-17
Sex
Male
Female
Racef
White only
Black only or in
combination with
some other race
Other
Ethnicity
Hispanic
Non-Hispanic

A
Completed
(n)

B
Interim
C
D
likely to be
Finalized
Total
completedb nonresponsec interimd
(n)
(n)
(n)

Unweighted
predicted response
rate for baseline,
based on predictor
samplee
(%)

Weighted predicted
response rate for
baseline, based on
predictor samplee
(%)

964

106

195

80.9

81.2

481
475

23
36

41
65

85
104

83.1
79.3

83.7
79.6

475
489

31
28

56
50

99
96

80.3
81.4

80.6
81.9

703
154

47
7

85
13

153
21

79.7
85.9

80.2
85.7

79.4

79.6

269
695

23
35

42
63

40
155

83.3
79.9

83.9
80.3

Note: The projected response rate for baseline is 75 percent.
a The characteristics are as sampled. That is, information on the characteristics was collected in the Household Screener.
b Interim likely to be completed is the sum of: (1) the product of the number of ever refused interim cases and the estimated proportion
of ever refused interim cases that will ultimately result in completes, and (2) the product of the number of never refused interim cases
and the estimated proportion of never refused interim cases that will ultimately result in completes.
c Finalized nonresponse includes refused cases and all other nonresponding cases.
d Total interim includes ever refused interim cases and never refused interim cases.
e Predicted response rate = (A+B)/(A+C+D).
f The sum of counts for this category do not sum to the overall total due to missing values. The number of missing cases is 8 for age and
34 for race.

Population Assessment of Tobacco and Health Study

Response Rates Associated with the
Biospecimen Collections

This section is on the method and response rates for the collection of buccal cell, urine, and blood
samples from adults who completed Adult Extended Interviews. Biospecimens are intended to
provide a basis for the assessment of between-person differences and within-person changes in
markers of tobacco exposure, and to detect and compare indicators of conditions and related disease
processes associated with the use of tobacco products. Field interviewers collected the buccal cell
and urine samples; on separate visits, phlebotomists collected the blood samples.

4.1

Method

As of February 26, 2014, 1,991 adults in the predictor sample had completed the Adult Extended
Interview and were eligible to provide biospecimens. Table 4-1 provides overall predicted
unweighted and weighted response rates for the biospecimen collections, and responses rates for
tobacco use status and demographic subgroups. All response rates are conditional on a completed
Household Screener and a completed Adult Extended Interview. The response rates were calculated
using the following formula:
RRU = Number of samples collected/number of Adult Extended Interviews completed
This formula was used to compute the projected biospecimen response rates presented in
Attachment 22 for the baseline wave. The denominator for the rate, the 1,991 adults who completed
the Adult Extended Interview, is the same for each of the biospecimen response rates.
In addition to the overall row, the table includes rows on tobacco use status, age, sex, race, and
ethnicity subgroups. Information from the Adult Extended Interview is used to define the tobacco
use status and demographic characteristics for the responding and nonresponding adults. Adults
with missing values for such characteristics were excluded from the response rate calculation for that
characteristic.

Table 4-1.

PATH Study baseline predicted response rates for the predictor sample, by respondent characteristics: Biospecimen
collections
Biospecimen
Buccal

Characteristica

A
Adult
Extended
Interviews
completed
(n)

B
Collected
(n)

Unweighted
predicted
response rate
for baseline,
based on
predictor
samplec
(%)

Urine
Weighted
predicted
response rate
for baseline,
based on
predictor
samplec
(%)

Blood

B
Collected
(n)

Unweighted
predicted
response rate
for baseline,
based on
predictor
samplec
(%)

Weighted
predicted
response rate
for baseline,
based on
predictor
samplec (%)

B
Collected
(n)

Unweighted
predicted
response rate
for baseline,
based on
predictor
samplec
(%)

Weighted
predicted
response rate
for baseline,
based on
predictor
samplec
(%)

1,991

1,408

70.7

69.0

1,253

62.9

61.8

734

36.9

Tobacco Status
Sampled as user
Sampled as non-user

1,416
575

1,039
369

73.4
64.2

72.7
63.9

919
334

64.9
58.1

64.5
58.2

535
199

37.8
34.6

38.6
34.6

523
742
530
195

389
535
352
132

74.4
72.1
66.4
67.7

74.6
71.2
64.1
67.4

340
473
319
121

65.0
63.7
60.2
62.1

65.4
63.0
59.3
60.6

173
279
201
81

33.1
37.6
37.9
41.5

32.9
36.6
37.3
41.6

1,034
955

697
711

67.4
74.5

65.8
72.3

625
628

60.4
65.8

59.1
64.8

350
384

33.8
40.2

34.2
39.8

1,433
309

1,004
225

70.1
72.8

68.7
70.1

894
195

62.4
63.1

61.6
60.5

539
116

37.6
37.5

38.1
35.9

196

143

73.0

69.6

130

66.3

64.9

29.6

28.8

341
1,616

248
1,134

72.7
70.2

72.6
68.1

229
1,000

67.2
61.9

67.6
60.5

121
599

35.5
37.1

36.3
37.0

Ageb
18-24
25-44
45-64
65+
Sexb
Male
Female
Raceb
White only
Black only or in combination
with some other race
Other
Ethnicityb
Hispanic
Non-Hispanic

Note: Table covers respondents who completed the Adult Extended Interview. The projected response rates for buccal and urine for baseline were 80 percent in Attachment 22; the projected
response rate for blood for baseline was 65 percent in Attachment 22.
a The characteristics are as reported in the Adult Extended Interview.
b The sum of counts for this category do not sum to the overall total due to missing values. The number of missing cases is 1 for age, 2 for sex, 53 for race, and 34 for ethnicity.
c Predicted response rate = B/A.

Population Assessment of Tobacco and Health Study

Overall

Population Assessment of Tobacco and Health Study

4.2

Results
Buccal Cells

The weighted predicted response rate for buccal cells is 69.0 percent, the projected response rate is
80 percent, and the worst-case response rate is 73 percent. The differential weighted response rate
for subgroups of respondents ranges from 1.4 percentage points for ethnicity to 10.5 percentage
points for age. The response rate for buccal cell collection based on the predictor sample is lower
than projected and than the worst-case scenario discussed in Attachment 22.

Urine
The weighted predicted response rate for urine is 61.8 percent, the projected response rate is 80
percent, and the worst-case response rate is 49 percent. The differential weighted response rate for
subgroups of respondents ranges from 4.4 percentage points for race to 6.3 percentage points for
tobacco use status. The response rate for urine collection based on the predictor sample is lower
than projected, but it exceeds the worst-case scenario discussed in Attachment 22.

Blood
The weighted predicted response rate for blood is 36.9 percent, the projected response rate is 65
percent, and the worst-case response rate is 39 percent. The differential weighted response rate for
subgroups of respondents ranges from 4.0 percentage points for tobacco use status to 9.3
percentage points for race. The response rate for blood collection based on the predictor sample is
lower than projected and than the worst-case scenario in Attachment 22.

Population Assessment of Tobacco and Health Study

Nonresponse Bias Analysis

This nonresponse bias analysis investigates possible differences between estimates calculated from
the PATH Study and independent estimates of those quantities from other surveys and censuses. By
so doing, the Study can assess the extent to which differential nonresponse among population
subgroups may affect estimates. Results are presented on the characteristics of respondents to the
Household Screener, Adult Extended Interview, and Youth Interview, and on adults from whom
biospecimens were collected for the PATH Study.

5.1

Method

Section 1.2 describes the selection of the predictor sample that is used as the basis of the
nonresponse bias analysis in this section. The predictor sample consists of 455 segments with
representation from all 156 PSUs in the PATH Study sample.
Assessment of potential nonresponse bias begins by comparing estimates of demographic counts
from the predictor sample with corresponding estimates from the American Community Survey
(ACS). The 1-year (2012) ACS estimates, calculated from the 2012 ACS Public Use Microdata
Sample (PUMS), were used for comparison purposes. These estimated demographic counts from
the ACS PUMS excluded institutional group quarters and persons in noninstitutional group quarters
who are not college students. These exclusions correspond to the target population for the PATH
Study.
The PATH Study measures a range of tobacco use behaviors; many of these variables are not
available in other studies. Responses to the PATH Study questions on current cigarette smoking,
however, can be compared with estimates from other surveys that ask about cigarette smoking
behavior. The following surveys were used for comparison: the Tobacco Use Supplement to the
Current Population Survey, 2010-2011 (TUS-CPS); the National Health and Nutrition Examination
Survey, 2011-2012 (NHANES); the National Health Interview Survey, 2012 (NHIS); the National
Survey on Drug Use and Health, 2012 (NSDUH); and the National Youth Tobacco Survey, 2012
(NYTS). Appendix A describes the questions used to define current smoking on each of these

Population Assessment of Tobacco and Health Study

surveys as well as the PATH Study, and outlines differences in target populations and question
ordering among the surveys.
The PATH Study oversamples young adults, African-American adults, and adult tobacco users.
Consequently, unweighted estimates of population quantities would be expected to be biased. In this
section, the inverse-probability-of-selection (IPS) weights, calculated using the probabilities of
selection, are used to estimate population quantities. Without nonresponse, estimates calculated
using the IPS weights would be expected to accord with the population counts.
The IPS weights were calculated in two stages. First, the household-level IPS weights were
calculated for all households sampled (responding households and nonresponding households) as
the inverse of the selection probability:

where
is the probability that household in segment of PSU is selected to be in the sample.
For the predictor sample, addresses were sampled directly from the USPS CDSF, so that Pijk is the
product of the PSU, the segment-within-PSU, and the address-within-segment selection
probabilities.
For nonresponse bias assessment purposes, the person-level IPS weights were computed using
HHIPSWT. For youth ages 12-17, these were calculated as

Probability youth

(

)selected for sample

Most selected households had fewer than 3 youths who were then selected with certainty, so that for
most households, the youth IPS weight is the same as the household-level IPS weight.
Adults were selected with different probabilities according to their age, race, and tobacco use status.
The adult IPS weights were calculated as

Probability adult

(

)selected for sample

Population Assessment of Tobacco and Health Study

The sampling of adults is performed in two phases. Phase 1 selects adults based on responses to the
Household Screener. The probability that adult in the household is selected for the Phase 1 sample
is a function of the number of adults in the household and of the ages, races, and tobacco use
statuses reported for those adults by the household respondent. Adults sampled at Phase 1 are
individually asked questions about their age, race, and tobacco usage, and are subsampled for Phase
2 on the basis of their responses to these questions. The adults subsampled for Phase 2 are then
administered the Adult Extended Interview. The probability in the formula for AIPSWT is the
product of the first-phase and second-phase selection probabilities.
Note that no nonresponse adjustments are performed for the calculation of IPS weights. The
weights HHIPSWT, YIPSWT, and AIPSWT are used for all calculations employing IPS weights that
are reported in Section 5.2. For the tables presented in Section 5.2, the unweighted counts include
categories for missing values. The estimates of percentages calculated using weights, however,
exclude respondents with missing values for that item. The estimates calculated from other surveys
that are used for comparison purposes also exclude missing values, except where noted.
Rao-Scott tests for goodness of fit (Rao and Scott, 1981, 1984, 1987) are used to assess the statistical
significance of differences between demographic estimates from the PATH Study predictor sample
and the comparison quantities from the 2012 ACS (using the 1-year estimates, as described at the
beginning of this section). The test assumes that the quantities calculated from the ACS are fixed
values without sampling error; therefore, the p-values for the Rao-Scott tests reported in this
document use slightly underestimated standard errors. This means that the p-values may be slightly
smaller than they would be if sampling errors in the ACS were taken into account. Small p-values
indicate that the estimates from the PATH Study predictor sample are significantly different from
the quantities in the ACS. Different criteria may be used for what is considered “small” and in
general, the interpretation of a p-value from a goodness of fit test depends on the sample size (see
for example Royall, 1986); the p-value for an effect size of three percentage points will be smaller for
a sample of 10,000 than for a sample of size 100. In this report, p-values less than 0.05 are
considered to indicate significant differences. A p-value greater than 0.05 indicates no significant
difference between the PATH Study estimate and the comparison quantity from the ACS, and, thus,
no reason to conclude that bias due to that characteristic would affect the PATH Study.
Confidence intervals are provided for estimates of cigarette smoking prevalence from the predictor
sample. These are constructed using the weight AIPSWT for adult estimates and weight YIPSWT
for youth estimates. The PATH Study estimates may then be compared to other surveys by
determining whether the point estimate from the external survey falls within the 95 percent
19

Population Assessment of Tobacco and Health Study

confidence interval constructed from the PATH Study.7 Taylor linearization is used to calculate the
variance, incorporating the complex sampling features of stratification and clustering. SAS software
version 9.3 (SAS Institute, 2011) was used to calculate all estimates.

5.2

Results

The first set of tables looks at estimates derived from the Household Screener. The demographic
quantities are estimated using the roster of household members, with their characteristics provided
by the household respondent. The household-level IPS weight HHIPSWT is used in Tables 5-1
through 5-5 to evaluate potential nonresponse bias. If nonresponse is not associated with
demographic characteristics, then the percentages calculated using HHIPSWT will be close to those
from the ACS.
Table 5-1 presents the unweighted counts and estimated population percentages of adults in the four
race/age domains used for sampling adults within households. These counts are from the
enumeration of adults done in the Household Screener. The ACS provides comparison quantities
for these four domains. The IPS-weighted estimates of percentages in each of the four domains,
calculated excluding the missing values, are similar to the 1-year 2012 ACS estimates. The Rao-Scott
p-value for goodness of fit is 0.82, indicating that the PATH Study estimates are not significantly
different from the ACS percentages. No evidence was found to indicate nonresponse bias with
respect to these four demographic domains.

This method will give a guideline for the correspondence between PATH Study estimates of smoking and those
obtained from other surveys. It does not include the sampling error from the external surveys, however, and therefore
does not exactly correspond to a significance test comparing the two surveys. A confidence interval for the difference
between the PATH Study estimate and the estimate from another survey would be wider than the confidence intervals
reported here, because it would also account for the sampling error of the other survey.

Population Assessment of Tobacco and Health Study

Table 5-1.

Race by age distribution, based on the household enumeration

Race and age
classification
Black* 18-24
Black* 25+
Non-Black 18-24
Non-Black 25+
Missing age or race
Total
p-value

Weighted percentage,
using household IPS
weights
2.1%
10.9%
11.2%
75.8%

Unweighted count
233
1,238
1,269
8,401
332
11,473

100.0%
0.82

Percentage from ACS
PUMS
2.1%
10.3%
10.9%
76.7%
100.0%

*Black alone or in combination with other races(s).

Table 5-2 compares the sex of the adults enumerated on the PATH Study household rosters with
the 1-year 2012 ACS distribution. The Rao-Scott p-value for goodness of fit is 0.66, indicating that
the PATH Study estimates are not significantly different from the ACS percentages.
Table 5-2.

Distribution of male and female adults listed in the household enumeration

Sex
Male
Female
Missing
Total
p-value

Weighted percentage for
adults, using
household IPS weights
47.8%
52.2%

Unweighted count
5,478
5,970
25
11,473

Percentage from ACS
PUMS
48.0%
52.0%

0.66

Table 5-3 compares the distribution of household size for the responding households with the
independent estimates of those quantities derived from the 1-year 2012 ACS. The PATH Study
appears to be obtaining fewer single-person households than occur in the ACS (p-value < 0.0001).
The PATH Study also has a lower percentage of single-adult households (Table 5-4) and, probably
related to this pattern, a slightly higher percentage of households with youth ages 12-17 than found
in the ACS (Table 5-5). Surveys commonly achieve a slightly lower percentage of one-person
households because they have fewer members available for contact.8 If no further weighting
adjustments were performed then to the extent that household size is associated with the PATH
Study’s outcomes, those outcomes may be affected by nonresponse bias. However, this concern is
addressed by the weighting adjustments and results described in Section 6.

See Brault (2013), who found a similar pattern in the CPS ASEC content test. Data collection for the predictor sample
of the PATH Study is not finalized, so this distribution may change as more data are collected.

Population Assessment of Tobacco and Health Study

Table 5-3.

Distribution of household size based on households responding to the Household
Screener

Number of persons in
household who are
not on active duty
0-1*
2
3
4
5+
Total
p-value

Weighted percentage,
using household IPS
weights
23.2%
31.8%
17.8%
15.0%
12.3%
100.0%
< 0.0001

Unweighted count
1,308
1,803
1,005
851
688
5,655

Percentage from ACS
PUMS
27.9%
33.7%
15.7%
13.0%
9.7%
100.0%

*A small number of households contain only emancipated youth and/or adults on active duty, and hence contribute to the zero part of
this category.

Table 5-4.

Distribution of number of adults based on households responding to the Household
Screener

Number of adults in
household who are
not on active duty
0-1
2
3+
Missing
Total
p-value

Table 5-5.

Weighted percentage,
using household IPS
weights
28.8%
50.8%
20.4%

Unweighted count
1,620
2,860
1,156
19
5,655

100.0%
< 0.0001

Percentage from ACS
PUMS
33.8%
50.6%
15.6%
100.0%

Distribution of number of youth ages 12-17 based on households responding to the
Household Screener

Number of youth ages
12-17 in household
0
1
2+
Missing
Total
p-value

Weighted percentage,
using household IPS
weights
82.9%
11.6%
5.4%

Unweighted count
4,679
651
306
19
5,655

100.0%
0.01

Percentage from ACS
PUMS
84.3%
11.2%
4.5%
100.0%

Tables 5-6 and 5-7 are based on adults in the predictor sample responding to the Adult Extended
Interview. The PATH Study oversamples young adults, African-American adults, and tobacco users,
so estimates calculated without weights will not accord with population estimates. The IPS-weighted
estimates are calculated using the adult weight AIPSWT; if the PATH Study had full response, it
would be expected that the IPS-weighted estimates would be close to the corresponding population

Population Assessment of Tobacco and Health Study

quantities. Table 5-6 presents the estimated race, ethnicity, and sex/age distributions from adults in
the predictor sample responding to the Adult Extended Interview. Additional columns in the table
present the weighted distributions, using weight AIPSWT, for the adults from whom urine, buccal,
and/or blood specimens were collected.
The IPS-weighted estimates of percent male/female are close to the 1-year 2012 ACS percentages,
for the adults in the predictor sample responding to the Adult Extended Interview and for those
providing each type of biological specimen. Persons ages 25-44 are overrepresented among the
adults responding to the Adult Extended Interview, however, and among those who provide urine
and buccal cell specimens. The nonresponse-adjusted weights in Section 6, which calibrate to age
groups, correct for this discrepancy.
Table 5-6 shows that the estimated percentages in different race and ethnicity groups, calculated
using adults responding to the Adult Extended Interview, or using those who provide blood
specimens, are not significantly different from the 1-year 2012 ACS estimates of those quantities.
The race distributions of adults who provide urine and buccal cells also accord with the ACS
distribution. Hispanic adults, however, are significantly more likely to provide urine or buccal cell
specimens.
Table 5-7 compares Adult Extended Interview respondents and those from whom biological
specimens were collected on other quantities that are measured in the ACS: education level and
presence of health insurance. The adults responding to the Adult Extended Interview, and those
contributing biological specimens, are approximately equally likely to have health insurance as
respondents to the 2012 ACS. The education level of the adults responding to the Adult Extended
Interview, however, tends to be higher than that in the ACS, although that is not the case for the
adults contributing biospecimens. In general, education level is associated with tobacco use status
(Agaku et al., 2014); the nonresponse-adjusted weights described in Section 6 adjust for educational
attainment.

Table 5-6.

Sex
Male
Female
Missing
Total
p-value

Total
p-value
Race
Black, alone or in combination
White alone
Other
Missing
Total
p-value
Ethnicity
Hispanic
Non-Hispanic
Missing
Total
p-value

48.7%
51.3%

641
642
0
1,283

0.65
523
742
530
195
1
1,991

12.2%
40.0%
31.6%
16.2%

13.7%
76.2%
10.1%

352
482
328
121
0
1,283

17.3%
82.7%

0.13

13.0%
40.7%
30.6%
15.7%

195
917
135
36
1,283

12.7%
76.5%
10.8%

405
547
362
132
0
1,446

19.8%
80.2%

0.01

357
398
0
755

13.5%
41.1%
29.5%
16.0%

225
1,033
149
39
1,446

13.2%
76.6%
10.2%

182
285
206
82
0
755

19.2%
80.8%

0.02

48.0%
52.0%
100.0%

11.7%
37.7%
32.4%
18.3%

13.0%
34.4%
34.8%
17.8%

0.44
116
557
60
22
755

0.60
264
1156
26
1,446

45.5%
54.5%

Percentage
from ACS
PUMS

0.33

0.0004

0.86
241
1,018
24
1,283

46.7%
53.3%

Adults from whom blood
specimen is collected
Weighted
percentage,
Unweighted
using adult
count
IPS weights

0.50

0.002

0.40
341
1,616
34
1,991

716
730
0
1,446

0.60

0.001
309
1,433
196
53
1,991

47.0%
53.0%

Adults from whom buccal
specimen is collected
Weighted
percentage,
Unweighted
using adult
count
IPS weights

12.5%
79.8%
7.7%

12.4%
76.0%
11.6%

0.07
127
614
14
755

17.4%
82.6%

0.27

14.7%
85.3%

Population Assessment of Tobacco and Health Study

Age group
18-24
25-44
45-64
65+
Missing

1,034
955
2
1,991

Adults from whom urine
specimen is collected
Weighted
percentage,
Unweighted
using adult
count
IPS weights

Table 5-7.

Comparison of education level and health insurance status based on adults responding to the Adult Extended Interview,
and on adults from whom urine, buccal, and/or blood specimens were collected
Adult respondents to Adult
Extended Interview
Weighted
percentage,
Unweighted
using adult
count
IPS weights
258
550
716
299
151
17
1,991

11.9%
24.3%
33.5%
18.3%
12.1%

192
342
470
185
89
5
1,283

0.02
1,532
438
21
1,991

83.2%
16.8%

0.79

14.3%
22.9%
34.6%
18.2%
9.9%

Adults from whom buccal
specimen collected
Weighted
percentage,
Unweighted
using adult
count
IPS weights
203
407
533
200
100
3
1,446

0.10
988
288
7
1,283

82.6%
17.4%

0.81

13.2%
24.6%
34.8%
17.3%
10.2%

Adults from whom blood
specimen collected
Weighted
percentage,
Unweighted
using adult
count
IPS weights
129
206
263
100
57
0
755

0.27
1,113
326
7
1,446

82.7%
17.3%

0.91

15.4%
25.0%
33.0%
16.5%
10.0%

Percentage
from ACS
PUMS
13.4%
28.0%
31.6%
17.3%
9.7%
0.0%
100.0%

0.62
590
163
2
755

83.2%
16.8%

0.87

82.9%
17.1%
0.0%
100.0%

Population Assessment of Tobacco and Health Study

Education
< HS
HS or GED
Some college, no degree
Bachelor degree
> Bachelor degree
Missing
Total
p-value
Health insurance
Yes
No
Missing
Total
p-value

Adults from whom urine
specimen collected
Weighted
percentage,
Unweighted
using adult
count
IPS weights

Population Assessment of Tobacco and Health Study

Table 5-8 presents the estimates of prevalence of current cigarette smoking9 for the adults
responding to the Adult Extended Interview, for the adult population as a whole and for subgroups.
These estimates are accompanied by 95 percent confidence intervals for the percentage of current
cigarette smokers for the PATH Study estimates. The last five columns present external estimates of
smoking prevalence from TUS-CPS, NHIS, NHANES, and NSDUH, respectively, along with 95
percent confidence intervals from those surveys. The estimates of smoking prevalence from each
survey were calculated excluding responses of “don’t know” and missing values.
The estimates of current smoking prevalence differ substantially from survey to survey. Many
potential reasons can explain these disparities, including that each survey has sampling error. Beyond
that, however, the surveys differ in question order, context, design, and mode of administration.
In general, the TUS-CPS estimates of smoking prevalence are lower than estimates from the other
surveys, including the PATH Study. This may be related to the proxy responses used in the TUSCPS. The rotation group structure of the TUS-CPS may result in underestimates of smoking
prevalence, as smokers are more likely to drop out over the course of the panel survey (Song, 2013).
The PATH Study and NSDUH both use audio computer-assisted self-interviewing (ACASI)
administration for the tobacco usage questions so that the interviewer does not see the responses to
the questions. By contrast, TUS-CPS, NHIS, and NHANES have direct questioning by an
interviewer: NHIS and NHANES are conducted in person, and TUS-CPS is conducted in person
and by telephone. The contexts and purposes of these surveys also differ: CPS is a general survey on
unemployment, NHIS and NHANES are general health surveys, NSDUH is a cross-sectional survey
on substance use (including tobacco use) and health, including mental health, and the PATH Study
is a longitudinal cohort study of tobacco use behaviors and health. Other differences among the
questions used in the instruments of these different studies are outlined in Appendix A.

For the PATH Study, following common practice for tobacco surveys, a current smoker is someone who (1) has
smoked at least 100 cigarettes in his or her lifetime and (2) currently smokes every day or some days. The questions
used to define current smoking for each survey are given in Appendix A.

Table 5-8.

Current smoker

PATH Study: Weighted
percentage,
using adult IPS weights
[95% confidence
interval]
18.5%
[16.5%, 20.4%]
19.7%
[17.4%, 21.9%]
17.4%
[14.9%, 19.8%]
21.2%
[18.1%, 24.4%]
22.0%
[18.7%, 25.2%]
18.6%
[15.7%, 21.5%]
7.6%
[5.1%, 10.1%]
12.7%
[9.8%, 15.5%]
18.8%
[16.2%, 21.4%]

Percentage
from 20102011 TUS-CPS
[95%
confidence
interval]
16.1%
[15.8%, 16.3%]
18.0%
[17.7%, 18.4%
14.2%
[13.9%, 14.5%]
17.1%
[16.4%, 17.8%]
17.9%
[17.5%, 18.4%]
17.8%
[17.4%, 18.2%]
7.8%
[7.5%, 8.2%]
10.9%
[10.4%, 11.5%]
17.5%
[17.2%, 17.8%]

Percentage
from 2012 NHIS
[95%
confidence
interval]
18.0%
[17.4%, 18.6%]
20.4%
[19.5%, 21.3%]
15.8%
[15.0%, 16.5%]
17.3%
[15.4%, 19.1%]
21.5%
[20.4%, 22.6%]
19.5%
[18.5%, 20.5%]
8.9%
[8.0%, 9.7%]
12.5%
[11.3%, 13.7%]
19.6%
[18.9%, 20.4%]

Percentage
from 20112012 NHANES*
[95%
confidence
interval]
19.8%
[17.5%, 22.1%]
23.9%
[20.7%, 27.1%]
16.0%
[13.5%, 18.5%]
20.4%***
[13.7%, 27.1%]
23.3%
[20.0%, 26.7%]
21.3%
[18.3%, 24.2%]
9.2%
[6.7%, 11.7%]
16.6%
[13.7%, 19.5%]
20.2%
[17.0%, 23.3%]

Percentage from
2012 NSDUH,
original
definition**
[95% confidence
interval]
23.8%
[23.1%, 24.5%]
26.7%
[25.7%, 27.7%]
21.1%
[20.1%, 22.1%]
NA****

Percentage from
2012 NSDUH,
modified
definition
[95% confidence
interval]
21.9%
[21.2%, 22.7%]
24.9%
[23.7%, 26.0%]
19.3%
[18.5%, 20.1%]
NA

18.6%
[17.0%, 20.2%]
25.1%
[24.2%, 26.0%]

15.5%
[14.1%, 17.0%]
23.9%
[23.0%, 24.8%]

Sample
size
1,989

PATH Study:
Unweighted
percentage
35.8%

1,033

36.2%

954

35.5%

522

28.2%

742

42.2%

529

39.5%

195

22.6%

341

26.1%

1,197

38.7%

415

34.9%

22.1%
[17.8%, 26.5%]

NA
[NA]

16.7%
[15.6%, 17.7%]

20.8%
[16.6%, 24.9%]

22.8%
[21.1%, 24.6%]

20.2%
[18.6%, 21.9%]

1,989

28.3%

14.1%
[13.6%, 14.6%]
3.9%
[3.6%, 4.2%]

16.4%
[14.3%, 18.4%]
3.4%
[2.7%, 4.1%]

7.5%

12.7%
[12.4%, 12.9%]
3.4%
[3.3%, 3.5%]

1,989

14.7%
[13.1%, 16.2%]
3.8%
[3.1%, 4.5%]

*The smoking questions asked in NHANES for adults ages 20 and older differ from the questions asked for persons ages 12-19. The modes of administration also differ for the two age groups. The
NHANES estimates presented in this table are for adults ages 20 and older.
**NSDUH’s definition of a current cigarette smoker is someone who has smoked part or all of a cigarette in the past 30 days, which is more expansive than the definition used in the other surveys.
However, NSDUH contains questions on lifetime smoking and current smoking. The modified definition uses these questions to construct a measure of “current smoking” that is comparable to that
of the other surveys (Ryan et al., 2012). The construction of this variable is described in Appendix A. The estimates and confidence intervals for the NSDUH “original definition” (except for the “current
smoker, other non-Hispanic” estimate) are from the published tables (SAMHSA, 2013); the estimates and confidence intervals for the “modified definition” are calculated from the public use data
set. The estimate of current smoking for the “other non-Hispanic” group was not available from the published tables and it was also calculated from the public use data set.
*** The estimate is for adults 20-24 years old.
**** Detailed age information was not available in the public use file for NSDUH 2012.

Population Assessment of Tobacco and Health Study

Current smoker,
male
Current smoker,
female
Current smoker,
age 18-24
Current smoker,
age 25-44
Current smoker,
age 45-64
Current smoker,
age 65+
Current smoker,
Hispanic
Current smoker,
white nonHispanic
Current smoker,
other nonHispanic
Current smoker,
every day
Current smoker,
some days

Current cigarette smoking based on adults responding to the Adult Extended Interview

Population Assessment of Tobacco and Health Study

Table 5-8 indicates the IPS-weighted estimates of current smoking from the PATH Study are most
similar to estimates from NHIS and NHANES. The value from at least one of these surveys is
inside each of the 95 percent confidence intervals constructed from the PATH Study estimates.10
The estimates from TUS-CPS tend to be below the estimates from the PATH Study, NHIS, and
NHANES; the estimates from NSDUH tend to be above the estimates from the PATH Study,
NHIS, and NHANES. No evidence was found to indicate nonresponse bias in the PATH Study
with respect to cigarette smoking behavior among adults, because the PATH Study estimates fall
well within the range of estimates from comparable surveys.
Table 5-9 gives estimates of current cigarette smoking for the adults from whom urine, buccal,
and/or blood specimens were collected. The IPS-weighted estimates of smoking are slightly higher
for adults who contribute one of the biospecimens, but the differences are not statistically
significant. The confidence intervals for smoking among adults providing biospecimens are in line
with the estimates from external surveys. This pattern will continue to be monitored, and if needed,
an extra step of weighting for nonresponse may be performed for the analysis of biological
specimens, as described in Section 6.1.
Results in Tables 5-6 through 5-9 are based on adults in the predictor sample responding to the
Adult Extended Interview. Similar analyses were performed for the youth respondents. The
demographic estimates are given in Table 5-10 and estimates of cigarette smoking are given in Table
5-11.
Table 5-10 shows that the IPS-weighted estimates of percentages of youth who are male/female and
ages 12-13/14-17 are not significantly different from the 1-year 2012 ACS percentages. The PATH
Study estimate of the percent of youth who are Hispanic, however, is approximately 7 percentage
points higher than the corresponding estimate from ACS, indicating that Hispanic youth are more
likely to respond to the PATH Study survey.

If a 95% confidence interval for percentage of adults who are current smokers from the PATH Study includes a fixed
value x, then a hypothesis test of the null hypothesis that the percentage of adults who are current smokers equals x
would have p-value > 0.05 and therefore the difference between the PATH Study estimate and the estimate from the
external survey is not statistically significant.

Table 5-9.

Current cigarette smoking based on adults from whom biospecimens were collected

Adult respondent to
Adult Extended
Interview
Adults providing urine
Adults providing buccal
Adults providing blood

Sample
size
1,989

1,281
1,445
755

Percentage from
2010-2011 TUSCPS
[95% confidence
interval]
16.1%
[15.8%, 16.3%]

Percentage from
2012 NHIS
[95% confidence
interval]
18.1%
[17.4%, 18.6%]

Percentage from
2011-2012
NHANES
[95% confidence
interval]
19.8%
[17.5%, 22.1%]

Percentage from
2012 NSDUH,
original definition*
[95% confidence
interval]
23.8%
[23.1%, 24.5%]

Percentage from
2012 NSDUH,
modified definition
[95% confidence
interval]
21.9%
[21.2%, 22.7%]

20.7%
[18.3%, 23.1%]
20.9%
[18.5%, 23.2%]
21.5%
[18.3%, 24.6%]

16.1%
[15.8%, 16.3%]
16.1%
[15.8%, 16.3%]
16.1%
[15.8%, 16.3%]

18.1%
[17.4%, 18.6%]
18.1%
[17.4%, 18.6%]
18.1%
[17.4%, 18.6%]

19.8%
[17.5%, 22.1%]
19.8%
[17.5%, 22.1%]
19.8%
[17.5%, 22.1%]

23.8%
[23.1%, 24.5%]
23.8%
[23.1%, 24.5%]
23.8%
[23.1%, 24.5%]

21.9%
[21.2%, 22.7%]
21.9%
[21.2%, 22.7%]
21.9%
[21.2%, 22.7%]

* NSDUH’s definition of a current cigarette smoker is someone who has smoked part or all of a cigarette in the past 30 days. However, NSDUH contains questions on lifetime smoking and
current smoking. The modified definition uses these questions to construct a measure of “current smoking” that is comparable to that of the other surveys (Ryan et al., 2012). The
construction of this variable is described in Appendix A.

Population Assessment of Tobacco and Health Study

PATH Study:
Weighted
cigarette
smoking
prevalence,
using adult IPS
weights
[95% confidence
interval]
18.5%
[16.5%, 20.4%]

Population Assessment of Tobacco and Health Study

Table 5-10.

Demographic distributions based on youth ages 12-17 who completed the Youth
Interview
Weighted percentage,
using youth IPS weights

Unweighted count
Sex
Male
Female
Missing
Total
p-value
Age group
12-13
14-17
Missing
Total
p-value
Race/ethnicity
Hispanic
Non-Hispanic white alone
Non-Hispanic other
Missing
Total
p-value

475
489
0
964

340
624
0
964

278
482
184
20
964

Percentage from ACS
PUMS

49.0%
51.0%

51.0%
49.0%

100.0%
0.25

100.0%

35.2%
64.8%

33.7%
66.3%

100.0%
0.28

100.0%

29.3%
51.4%
19.3%

21.9%
55.2%
22.9%

100.0%
0.0002

100.0%

Table 5-11.

Cigarette smoking* based on youth ages 12-17 who completed the Youth Interview

Sample
size
Ever tried cigarette smoking,
964
even one or two puffs
Ever tried smoking, male
475

PATH Study:
Unweighted
percentage
14.7%
14.5%

489

14.9%

Ever tried smoking,
age 12-13
Ever tried smoking,
age 14-17
Have smoked in past
30 days

340

5.3%

624

19.9%

962

3.5%

* Defined as ever tried a cigarette, even one or two puffs.

Percentage from
2011-2012 NHANES
[95% confidence
interval]
20.5%
[17.5%, 23.6%]
21.1%
[15.9%, 26.3%]
20.0%
[14.6%, 25.5%]
5.6%
[1.9%, 9.4%]
28.3%
[23.5%, 33.0%]
6.9%
[4.0%, 9.8%]

Percentage
from 2012
NSDUH
[95%
confidence
interval]
17.4%
[16.7%, 18.1%]
18.4%
[17.4%, 19.4%]
16.4%
[15.5%, 17.3%]
4.8%
[4.2%, 5.4%]
23.5%
[22.5%, 24.7%]
6.6%
[6.2%, 7.0%]

Percentage
from 2012
NYTS
[95%
confidence
interval]
25.6%
[23.6%, 27.6%]
27.2%
[25.0%, 29.3%]
24.0%
[21.8%, 26.2%]
11.8%
[10.2%, 13.4%]
32.5%
[30.0%, 34.9%]
8.7%
[7.7%, 9.8%]

Population Assessment of Tobacco and Health Study

Ever tried smoking, female

PATH Study:
Weighted
percentage,
using youth IPS
weights
[95% confidence
interval]
14.7%
[12.2%, 17.2%]
14.4%
[11.3%, 17.5%]
15.0%
[11.6%, 18.4%]
5.0%
[2.9%, 7.1%]
20.0%
[16.5%, 23.4%]
3.4%
[2.4%, 4.4%]

Population Assessment of Tobacco and Health Study

Table 5-11 estimates one common measure of cigarette smoking prevalence among youth
respondents, along with 95 percent confidence intervals. These are compared with estimates from
NHANES, NSDUH, and NYTS.11 Different measures of smoking are used in this report for youth
than for adults. The measure of cigarette smoking used for youth is whether the youth has ever tried
smoking a cigarette, even one or two puffs (see Appendix A).
Differences among the youth surveys might lead to differences in their estimates. In addition, the
youth survey estimates have sampling error, as demonstrated by the confidence intervals about the
estimates from the comparison surveys. Questions and their orderings also differ among the surveys,
as described in Appendix A, as do the modes of administration. The PATH Study, NHANES, and
NSDUH use ACASI for the questions about tobacco usage by youth, and these are administered
individually in a household or mobile examination center setting. The NYTS is a pencil-and-paper
survey administered in the classroom. Currivan et al. (2004) found that even when telephone ACASI
was used, estimates of youth smoking prevalence were much lower for a telephone survey of youth
smoking than in a school-based survey of the same population (see also Fowler and Stringfellow,
2001, for a discussion of higher smoking rates in school-based surveys).
Based on the predictor sample, the PATH Study’s estimates of the youth smoking measure appear
to be slightly lower than the estimates from NHANES and NSDUH. Part of this difference may be
sampling error and part may be attributable to differences among the survey wordings and
administrations. Moreover, the comparison surveys are from different time periods. According to
SAMHSA (2013), cigarette smoking among teens is dropping (from 2011 to 2012, it dropped by 0.8
percentage points among 12-13 year olds, 1.3 percentage points among 14-15 year olds, and 2.5
percentage points among 16-17 year olds). The lower percentages found by the PATH Study may
reflect, in part, a continuation of this trend. However, some of the differences among the estimates
of youth smoking prevalence may be attributable to nonresponse bias or measurement error on the
part of one or more of the surveys.

TUS-CPS does not interview persons younger than 18 about tobacco use.

Population Assessment of Tobacco and Health Study

Statistical Approach for Addressing
Nonresponse
6.1

Computation of Nonresponse-Adjusted Weights

The primary approach for addressing nonresponse is to use differential weight adjustments. These
adjustments are done at the household level and at the person level. The weight adjustments
calibrate the estimates of demographic quantities such as age, race, and sex to values calculated from
the 1-year 2012 ACS (which are considered to be highly accurate because of the large sample size
and high response rate for the ACS). These adjustments correct for disparities among these
demographic quantities and also for other disparities that might be associated with the demographic
quantities. Among numerous sources, the handbook on household surveys by the United Nations
(2005, chapter 6) and Särndal and Lundström (2005) discuss the methods and theory of using weight
adjustments for nonresponse.

Household Nonresponse-Adjusted Weights
The household IPS weights were computed for all sampled addresses in the predictor sample.
However, some sampled addresses cannot be located/accessed, others are found to be ineligible
(e.g., vacant lots and group quarters), and some eligible households do not complete the Household
Screener. Adjustments were therefore made to the IPS weights of responding households to
compensate for the estimated number of nonresponding households that were eligible for the
PATH Study based on all the addresses in the sample for which eligibility status was determined.
This eligibility adjustment was done separately for each census region. Further adjustments were
made within weighting classes based on information available for both responding and
nonresponding households, namely the segments and blocks in which they are located. Census 2010
data were used to form weighting classes according to the percentage of occupied housing units, the
percentage of population that is Black,12 and the percentage of population that is Hispanic in the
census block containing the address. Census region and the urbanicity of the PSU were also used
when forming the weighting classes.

Black is defined as Black alone, or in combination with other races.

Population Assessment of Tobacco and Health Study

Then, within a weighting class, the IPS weights for the responding households were inflated
proportionately so that they produce the same sum as the sum of the IPS weights of the responding
and nonresponding households combined. The nonresponse-adjusted household weight is

sum of HH PS T for eligible sampled households in weighting class
sum of HH PS T for responding households in weighting class
The nonresponse-adjusted weights were then raked to the 1-year 2012 ACS household counts by
census region, tenure, and number of persons in the household. For raking purposes, tenure and the
number of persons were imputed for households missing this information using logical or hot-deck
imputation.13 The final raked household weight is
(raking ad ustment)

Person Nonresponse-Adjusted Weights
The raked household-level weight is used as the foundation for calculating the nonresponse-adjusted
person-level weights, for both youth and adults. The initial person-level nonresponse-adjusted
weight was computed as the product of the Household Screener raked weight HHRKWT and the
reciprocal of the within-household probability of selection for person within household of PSU
and segment as shown in the following formulas:

Probability adult selected at Phase 1 from household (
Probability youth selected from household (

)

The probability differs for adults and youth, as described in Section 5.1.
Similarly to the adjustment for Household Screener nonresponse, a nonresponse adjustment was
performed to account for nonrespondents to the Adult Extended Interview. The weights of
respondents to the Adult Extended Interview were inflated to account for the nonrespondents.

See Lohr (2010) for a brief description of raking and imputation methods.

Population Assessment of Tobacco and Health Study

For youth, the initial weights (YBWT) were raked to population totals from the 1-year 2012 ACS,
using Census region, age, race/ethnicity, and sex as raking variables. These variables were imputed,
either from the Household Screener or using hot-deck imputation, if they were missing. After
raking, the final weights for youth are denoted as YRKWT.
The final weights for adults were computed in three steps. First, a nonresponse adjustment was
performed using the tobacco use status, age, and sex reported in the Household Screener, separately
within the four Census regions. The resulting adult weight, adjusted for nonresponse between
Phases 1 and 2 of the adult sampling procedure, for respondents to the Phase 2 Screener, is

sum of AP1
T for adults sampled at Phase 1 in weighting class
sum of AP1
T for adults responding to Phase 2
in weighting class
Second, the probability of selection at Phase 2 was used to find the Phase 2 weight:

Probability adult from household (

) selected at Phase 2

Finally, the Phase 2 adult weights were raked to independent population totals based on data from
the 1-year 2012 ACS. The raking was done using combinations of Census region, age, race/ethnicity,
sex, and educational attainment. The final raked weight is
(raking ad ustment)
The adult raked weight ARKWT is also used for the analysis of adults in the predictor sample who
provide biospecimens. An additional stage of weighting may be used for biospecimens for the full
sample if needed, in which the weights are adjusted to accord with the adults responding to the
Adult Extended Interview and then re-raked to the independent population totals from the 1-year
2012 ACS. This adjustment would be performed separately for each type of biospecimen.
This section described the weighting procedure used for the predictor sample. A similar, though not
identical, weighting procedure will be used for the full sample from the PATH Study.

Population Assessment of Tobacco and Health Study

6.2

Results

In this section, results are presented on the evaluation of the performance of the nonresponseadjusted weights for variables of interest in the PATH Study. Tables 6-1 through 6-11 repeat the
analyses used to produce Tables 5-1 through 5-11, this time using the nonresponse-adjusted weights
described in Section 6.1. The estimates calculated using IPS weights are retained in these tables to
facilitate easy comparison of the estimates obtained using the two sets of weights. A p-value is given
for each of the IPS-weighted and raked-weighted estimates in each of Tables 6-1 through 6-7. The
p-value reported for the IPS-weighted estimate is the same as that given in the corresponding table
in Section 5: it assesses the statistical significance of the difference between the IPS-weighted
estimate from the PATH Study and the 1-year 2012 ACS quantity. The p-value reported for the
weighted percentage using the raked weights is for the comparison of the raked-weighted estimate
from the PATH Study to the same ACS quantity.
Table 6-1.

Race by age distribution, based on household enumeration

Race and age classification
Black* 18-24
Black* 25+
Non-Black 18-24
Non-Black 25+
Missing age or race
Total
p-value

Unweighted
count
233
1,238
1,269
8,401
332
11,473

Weighted
percentage,
using household IPS
weights
2.1%
10.9%
11.2%
75.8%
100.0%
0.82

Weighted
percentage,
using household
raked weights
1.7%
10.5%
9.4%
78.3%
100.0%
0.09

Percentage from
ACS PUMS
2.1%
10.3%
10.9%
76.7%
100.0%

*Black alone or in combination with other races(s).

The household raked weight HHRKWT adjusts the weights so that they agree with the 1-year 2012
ACS household counts by region, tenure, and household size. They would therefore not be expected
to bring person-level percentages of specific demographic groups closer to the ACS values. Tables
6-1 and 6-2 compare the estimated percentage of adults in the PATH Study household rosters to the
ACS values for each race/age and sex group using the raked weights. These estimated percentages
are not significantly different from the ACS quantities, although the IPS-weighted percentages are
closer to the ACS values. Table 6-6 demonstrates the effect of the person-level weighting
adjustments: using the raked adult weights, the race/age and sex distributions are practically identical
to those from the ACS.

Population Assessment of Tobacco and Health Study

Tables 6-3 through 6-5 examine the estimates of household size using the raked household weights;
as expected, the raked weights bring the estimated percentages in line with the 1-year 2012 ACS
values.
Table 6-2.

Distribution of male and female adults listed in the household enumeration

Sex
Male
Female
Missing
Total
p-value

Table 6-3.

Unweighted
count
5,478
5,970
25
11,473

Weighted
percentage for
adults,
using household IPS
weights
47.8%
52.2%

Weighted
percentage for
adults,
using household
raked weights
47.4%
52.6%

100.0%
0.66

100.0%
0.11

Percentage from
ACS PUMS
48.0%
52.0%
100.0%

Distribution of household size based on households responding to the Household
Screener

Number of persons in
household who are not on
active duty
0-1*
2
3
4
5+
Total
p-value

Unweighted
count
1,308
1,803
1,005
851
688
5,655

Weighted
percentage,
using household
IPS weights
23.2%
31.8%
17.8%
15.0%
12.3%
100.0%
< 0.0001

Weighted
percentage,
using household
raked weights
28.4%
33.5%
15.5%
12.9%
9.7%
100.0%
0.98

Percentage
from ACS PUMS
27.9%
33.7%
15.7%
13.0%
9.7%
100.0%

*A small number of households contain only emancipated youth and/or adults on active duty, and hence contribute to the zero part of
this category.

Table 6-4.

Distribution of number of adults based on households responding to the Household
Screener

Number of adults in
household who are not on
active duty
0-1
2
3+
Missing
Total
p-value

Unweighted
count
1,620
2,860
1,156
19
5,655

Weighted
percentage,
using household
IPS weights
28.8%
50.8%
20.4%
100.0%
< 0.0001

Weighted
percentage,
using household
raked weights
34.5%
50.6%
14.9%
100.0%
0.50

Percentage from
ACS PUMS
33.8%
50.6%
15.6%
100.0%

Population Assessment of Tobacco and Health Study

Table 6-5.

Distribution of number of youth ages 12-17 based on households responding to the
Household Screener

Number of youth ages
12-17 in household
0

Unweighted
count
4,679

Weighted
percentage,
using household
IPS weights
82.9%

Weighted
percentage,
using household
raked weights
84.7%

Percentage
from ACS PUMS
84.3%

651

11.6%

10.6%

11.2%

306

5.4%

4.8%

4.5%

100.0%
0.01

100.0%
0.31

100.0%

Missing
Total
p-value

19
5,655

Tables 6-6 and 6-7 present the estimates of demographic characteristics, education, and health
insurance based on adult respondents to the predictor sample, using the adult raked weight
ARKWT. The raking corrects for the slight overestimate in percentage of the 25-44 age group when
the IPS weights are used. Notably, the raking was performed on the adults responding to the Adult
Extended Interview, and no additional adjustments were performed on the adults from whom
biospecimens were collected. This raking brings the estimated age distribution in line with the 1-year
2012 ACS figures for the adults who provide each type of biospecimen as well. The raked estimates
of percentages in each race group accord with the ACS percentages for adults completing the
extended interview and for adults providing buccal cell or urine specimens. The race distribution for
the adults providing blood specimens, however, is marginally significantly different from the ACS
values when the raked weights are used. The PATH Study will continue to monitor this for the full
sample and if this pattern persists, may construct an additional set of weights for analyzing the blood
collection data. Table 6-7 shows that the raked estimates are not significantly different from the ACS
distributions for education and health insurance. For the adults responding to the extended
interview, the IPS-weighted estimates for percentages of adults at different education levels are
significantly different from the ACS comparison quantities, as indicated by the p-value of 0.02. The
p-value for comparing the raked-weighted estimates for education with the ACS estimates is 0.72,
indicating that the raked weights correct for the disparity in education.
Estimates of smoking prevalence in Table 6-8 using the raked weight ARKWT are very similar to
the estimates using the IPS weight AIPSWT, and both of these are in the range of values obtained
by other surveys. Table 6-9 gives estimates, using both sets of weights, of current cigarette smoking
prevalence for the adults from whom urine, buccal, and/or blood specimens were collected. No
additional weighting adjustments were performed to account for nonresponse to the biospecimen

Population Assessment of Tobacco and Health Study

collections. The raked estimates, using the subsets of respondents who provide each type of
biospecimen, are similar to the IPS-weighted estimates but are slightly closer to the estimated
smoking prevalence that is calculated using all adults responding to the Adult Extended Interview.
Tables 6-10 and 6-11 examine the effect of the raked weight YRKWT on estimates calculated from
the responding youth. The raked weights correct for the slight overrepresentation of Hispanics
among the youth in the predictor sample. They have little effect, however on the other demographic
characteristics (for which the IPS-weighted estimates already agreed with the 1-year 2012 ACS
figures) and estimates of smoking prevalence.

Table 6-6.

Demographic distributions based on adults responding to the Adult Extended Interview, and on adults from whom urine,
buccal, and/or blood specimens were collected
Adult respondents to
Adults from whom urine specimen is Adults from whom buccal specimen Adults from whom blood specimen is
Adult Extended Interview
collected
is collected
collected
Weighted
Weighted
Weighted
Weighted
Weighted percentage
Weighted percentage
Weighted percentage
Weighted percentage
percentage using adult
percentage using adult
percentage using adult
percentage using adult Percentage
Unweighted using adult
raked
Unweighted using adult
raked
Unweighted using adult
raked
Unweighted using adult
raked
from ACS
count
IPS weights weights
count
IPS weights
weights
count
IPS weights
weights
count
IPS weights
weights
PUMS

Sex
Male
Female
Missing

523
742
530
195
1
1,991

48.7%
51.3%

48.1%
51.9%

0.65

0.97

12.2%
40.0%
31.6%
16.2%

13.0%
34.5%
34.7%
17.8%

0.001

641
642
0
1,283

352
482
328
121
0
1,283

0.99

47.0%
53.0%

46.8%
53.2%

0.60

0.54

13.0%
40.7%
30.6%
15.7%

13.7%
35.6%
33.6%
17.1%

0.002

716
730
0
1,446

405
547
362
132
0
1,446

0.81

46.7%
53.3%

46.0%
54.0%

0.50

0.27

13.5%
41.1%
29.5%
16.0%

14.4%
35.9%
32.4%
17.3%

0.0004

357
398
0
755

182
285
206
82
0
755

0.44

45.5%
54.5%

44.6%
55.4%

0.33

0.13

11.7%
37.7%
32.4%
18.3%

12.4%
32.5%
35.7%
19.5%

0.44

0.73

48.0%
52.0%
100.0%

13.0%
34.4%
34.8%
17.8%

309

13.7%

13.0%

195

12.7%

12.2%

225

13.2%

12.6%

116

12.5%

11.7%

12.4%

1,433
196
53
1,991

76.2%
10.1%

77.4%
9.6%

917
135
36
1,283

76.5%
10.8%

77.0%
10.8%

1,033
149
39
1,446

76.6%
10.2%

76.9%
10.4%

557
60
22
755

79.8%
7.7%

81.0%
7.3%

76.0%
11.6%

0.40

0.38

0.86

0.90

0.60

0.77

0.07

0.05

17.3%
82.7%

15.0%
85.0%

19.8%
80.2%

17.6%
82.4%

19.2%
80.8%

17.1%
82.9%

17.4%
82.6%

15.9%
84.1%

0.13

0.84

0.01

0.14

0.02

0.21

0.27

0.63

341
1,616
34
1,991

241
1,018
24
1,283

264
1156
26
1,446

127
614
14
755

14.7%
85.3%

Population Assessment of Tobacco and Health Study

Total
p-value
Age group
18-24
25-44
45-64
65+
Missing
Total
p-value
Race
Black, alone or
in combination
White alone
Other
Missing
Total
p-value
Ethnicity
Hispanic
Non-Hispanic
Missing
Total
p-value

1,034
955
2
1,991

Table 6-7.

Comparison of education level and health insurance status based on adults responding to the Adult Extended Interview,
and on adults from whom urine, buccal, and/or blood specimens were collected
Adult respondents to
Adults from whom
Adults from whom
Adults from whom
Adult Extended Interview
urine specimen collected
buccal specimen collected
blood specimen collected
Weighted
Weighted
Weighted
Weighted
Weighted percentage
Weighted percentage
Weighted percentage
Weighted percentage
percentage using adult
percentage using adult
percentage using adult
percentage using adult Percentage
Unweighted using adult
raked
Unweighted using adult
raked
Unweighted using adult
raked
Unweighted using adult
raked
from ACS
count
IPS weights weights
count
IPS weights weights
count
IPS weights weights
count
IPS weights weights
PUMS
258
550
716

11.9%
24.3%
33.5%

13.0%
28.1%
31.4%

192
342
470

14.3%
22.9%
34.6%

15.6%
26.3%
32.7%

203
407
533

13.2%
24.6%
34.8%

14.3%
28.0%
32.8%

129
206
263

15.4%
25.0%
33.0%

16.4%
28.3%
31.1%

13.4%
28.0%
31.6%

299
151
17
1,991

18.3%
12.1%

16.4%
11.1%

185
89
5
1,283

18.2%
9.9%

16.4%
8.9%

200
100
3
1,446

17.3%
10.2%

15.7%
9.3%

100
57
0
755

16.5%
10.0%

14.8%
9.4%

17.3%
9.7%
0.0%
100.0%

0.02

0.72

0.10

0.52

0.27

0.78

0.62

0.48

83.2%
16.8%

83.9%
16.1%

82.6%
17.4%

82.9%
17.1%

82.7%
17.3%

83.0%
17.0%

83.2%
16.8%

84.2%
15.8%

0.79

0.44

0.81

0.99

0.91

0.95

0.87

0.51

1,532
438
21
1,991

988
288
7
1,283

1,113
326
7
1,446

590
163
2
755

82.9%
17.1%
0.0%
100.0%

Population Assessment of Tobacco and Health Study

Education
< HS
HS or GED
Some college, no
degree
Bachelor degree
> Bachelor degree
Missing
Total
p-value
Health insurance
Yes
No
Missing
Total
p-value

Table 6-8.

Current cigarette smoking based on adults responding to the Adult Extended Interview

Sample
size

PATH Study:
PATH Study:
Weighted
Weighted
percentage,
percentage,
using adult IPS using adult raked
PATH Study:
weights
weights
Unweighted [95% confidence [95% confidence
percentage
interval]
interval]

Percentage
from 20102011 TUS-CPS
[95%
confidence
interval]

Percentage from
Percentage from
2011-2012
2012 NHIS
NHANES*
[95% confidence [95% confidence
interval]
interval]

Percentage from
2012 NSDUH,
original
definition**
[95% confidence
interval]

Percentage from
2012 NSDUH,
modified
definition
[95% confidence
interval]

1,989

35.8%

18.5%
[16.5%, 20.4%]

18.1%
[16.0%, 21.1%]

16.1%
[15.8%, 16.3%]

18.0%
[17.4%, 18.6%]

19.8%
[17.5%, 22.1%]

23.8%
[23.1%, 24.5%]

21.9%
[21.2%, 22.7%]

Current smoker,
male

1,033

36.2%

19.7%
[17.4%, 21.9%]

20.0%
[17.4%, 22.6%]

18.0%
[17.7%, 18.4%

20.4%
[19.5%, 21.3%]

23.9%
[20.7%, 27.1%]

26.7%
[25.7%, 27.7%]

24.9%
[23.7%, 26.0%]

Current smoker,
female

954

35.5%

17.4%
[14.9%, 19.8%]

16.3%
13.9%, 18.7%]

14.2%
[13.9%, 14.5%]

15.8%
[15.0%, 16.5%]

16.0%
[13.5%, 18.5%]

21.1%
[20.1%, 22.1%]

19.3%
[18.5%, 20.1%]

Current smoker,
age 18-24

522

28.2%

21.2%
[18.1%, 24.4%]

21.3%
[17.9%, 24.7%]

17.1%
[16.4%, 17.8%]

17.3%
[15.4%, 19.1%]

20.4%***
[13.7%, 27.1%]

NA****

Current smoker,
age 25-44

742

42.2%

22.0%
[18.7%, 25.2%]

22.7%
[19.2%, 26.1%]

17.9%
[17.5%, 18.4%]

21.5%
[20.4%, 22.6%]

23.3%
[20.0%, 26.7%]

Current smoker,
age 45-64

529

39.5%

18.6%
[15.7%, 21.5%]

17.3%
[14.3%, 20.2%]

17.8%
[17.4%, 18.2%]

19.5%
[18.5%, 20.5%]

21.3%
[18.3%, 24.2%]

Current smoker,
age 65+

195

22.6%

7.6%
[5.1%, 10.1%]

8.5%
[5.7%, 11.4%]

7.8%
[7.5%, 8.2%]

8.9%
[8.0%, 9.7%]

9.2%
[6.7%, 11.7%]

Current smoker,
Hispanic

341

26.1%

12.7%
[9.8%, 15.5%]

13.0%
[9.9%, 16.2%]

10.9%
[10.4%, 11.5%]

12.5%
[11.3%, 13.7%]

16.6%
[13.7%, 19.5%]

18.6%
[17.0%, 20.2%]

15.5%
[14.1%, 17.0%]

Current smoker,
white non-Hispanic

1,197

38.7%

18.8%
[16.2%, 21.4%]

18.2%
[15.6%, 20.8%]

17.5%
[17.2%, 17.8%]

19.6%
[18.9%, 20.4%]

20.2%
[17.0%, 23.3%]

25.1%
[24.2%, 26.0%]

23.9%
[23.0%, 24.8%]

Current smoker,
other non-Hispanic

415

34.9%

22.1%
[17.8%, 26.5%]

21.6%
[17.7%, 25.5%]

16.7%
[15.6%, 17.7%]

20.8%
[16.6%, 24.9%]

22.8%
[21.1%, 24.6%]

20.2%
[18.6%, 21.9%]

Current smoker,
every day

1,989

28.3%

14.7%
[13.1%, 16.2%]

14.6%
[12.9%, 16.4%]

12.7%
[12.4%, 12.9%]

14.1%
[13.6%, 14.6%]

16.4%
[14.3%, 18.4%]

Current smoker,
some days

1,989

7.5%

3.8%
[3.1%, 4.5%]

3.5%
[2.8%, 4.1%]

3.4%
[3.3%, 3.5%]

3.9%
[3.6%, 4.2%]

3.4%
[2.7%, 4.1%]

Population Assessment of Tobacco and Health Study

Current smoker

Table 6-9.

Current cigarette smoking based on adults from whom biospecimens were collected

Sample
size

PATH Study:
PATH Study:
Weighted
Weighted
cigarette
cigarette
smoking
smoking
prevalence,
prevalence,
using adult IPS
using adult
weights
raked weights
[95% confidence [95% confidence
interval]
interval]

Percentage from
2010-2011 TUSCPS
[95% confidence
interval]

Percentage from
2012 NHIS
[95% confidence
interval]

Percentage from
2011-2012
NHANES
[95% confidence
interval]

Percentage from Percentage from
2012 NSDUH,
2012 NSDUH,
original
modified
definition*
definition
[95% confidence [95% confidence
interval]
interval]

Adult respondent to Adult
Extended Interview

1,989

18.5%
[16.5%, 20.4%]

18.1%
[16.0%, 20.1%]

16.1%
[15.8%, 16.3%]

18.1%
[17.4%, 18.6%]

19.8%
[17.5%, 22.1%]

23.8%
[23.1%, 24.5%]

21.9%
[21.2%, 22.7%]

Adults providing urine

1,281

20.7%
[18.3%, 23.1%]

19.9%
[17.4%, 22.4%]

16.1%
[15.8%, 16.3%]

18.1%
[17.4%, 18.6%]

19.8%
[17.5%, 22.1%]

23.8%
[23.1%, 24.5%]

21.9%
[21.2%, 22.7%]

Adults providing buccal

1,445

20.9%
[18.5%, 23.2%]

20.3%
[17.8%, 22.8%]

16.1%
[15.8%, 16.3%]

18.1%
[17.4%, 18.6%]

19.8%
[17.5%, 22.1%]

23.8%
[23.1%, 24.5%]

21.9%
[21.2%, 22.7%]

755

21.5%
[18.3%, 24.6%]

19.9%
[16.8%, 23.1%]

16.1%
[15.8%, 16.3%]

18.1%
[17.4%, 18.6%]

19.8%
[17.5%, 22.1%]

23.8%
[23.1%, 24.5%]

21.9%
[21.2%, 22.7%]

Adults providing blood

Population Assessment of Tobacco and Health Study

*NSDUH’s definition of a current cigarette smoker is someone who has smoked part or all of a cigarette in the past 30 days. However, NSDUH contains questions on lifetime smoking and current
smoking. The modified definition uses these questions to construct a measure of “current smoking” that is comparable to that of the other surveys (Ryan et al., 2012). The construction of this
variable is described in Appendix A.

Population Assessment of Tobacco and Health Study

Table 6-10.

Demographic distributions based on youth ages 12-17 who completed the Youth
Interview

Sex
Male
Female
Missing
Total
p-value
Age group
12-13
14-17
Missing
Total
p-value
Race/ethnicity
Hispanic
Non-Hispanic white alone
Non-Hispanic other
Missing
Total
p-value

Weighted percentage,
using youth raked
weights

Percentage
from ACS
PUMS

Unweighted
count

Weighted percentage,
using youth IPS weights

475
489
0
964

49.0%
51.0%

51.0%
49.0%

100.0%
0.25

100.0%
0.99

100.0%

35.2%
64.8%

35.6%
64.4%

33.7%
66.3%

100.0%
0.28

100.0%
0.20

100.0%

29.3%
51.4%
19.3%

22.3%
54.9%
22.7%

21.9%
55.2%
22.9%

100.0%
0.0002

100.0%
0.97

100.0%

340
624
0
964

278
482
184
20
964

Table 6-11.

Cigarette smoking* based on youth ages 12-17 who completed the Youth Interview

Ever tried cigarette smoking, even one or
two puffs
Ever tried smoking, male

PATH Study:
Sample Unweighted
size
percentage
964
14.7%
14.5%

Ever tried smoking, female

489

14.9%

Ever tried smoking, age 12-13

340

5.3%

Ever tried smoking, age 14-17

624

19.9%

Have smoked in past 30 days

962

3.5%

* Defined as ever tried a cigarette, even one or two puffs.

PATH Study:
Weighted
percentage,
using youth
raked weights
[95% confidence
interval]
14.7%
[12.0%, 17.5%]
14.7%
[11.2%, 18.1%]
14.8%
[11.0%, 18.5%]
5.2%
[2.6%, 7.8%]
20.0%
[16.2%, 23.7%]
3.5%
[2.3%, 4.7%]

Percentage from
2011-2012
NHANES
[95% confidence
interval]
20.5%
[17.5%, 23.6%]
21.1%
[15.9%, 26.3%]
20.0%
[14.6%, 25.5%]
5.6%
[1.9%, 9.4%]
28.3%
[23.5%, 33.0%]
6.9%
[4.0%, 9.8%]

Percentage from
2012 NSDUH
[95% confidence
interval]
17.4%
[16.7%, 18.1%]
18.4%
[17.4%, 19.4%]
16.4%
[15.5%, 17.3%]
4.8%
[4.2%, 5.4%]
23.5%
[22.5%, 24.7%]
6.6%
[6.2%, 7.0%]

Percentage from
2012 NYTS
[95% confidence
interval]
25.6%
[23.6%, 27.6%]
27.2%
[25.0%, 29.3%]
24.0%
[21.8%, 26.2%]
11.8%
[10.2%, 13.4%]
32.5%
[30.0%, 34.9%]
8.7%
[7.7%, 9.8%]

Population Assessment of Tobacco and Health Study

475

Population Assessment of Tobacco and Health Study

Discussion

This report by NIDA/FDA addresses the terms of clearance of OMB's approval (0925-0664 dated
August 23, 2013) of the PATH Study’s baseline wave of data and biospecimen collection. It covers
the first 5 months of the baseline (September 12, 2013 to February 26, 2014) and is based on the
predictor sample, the probability sample of addresses selected for the PATH Study and released to
field interviewers early in the field period.

7.1

Summary of Findings
Response Rates

As reported in Sections 2, 3, and 4, the weighted response rates14 for two of the PATH Study
interviews and the biospecimen collections based on the predictor sample are lower than projected
(see Table 6-1), and the weighted response rates for two biospecimen collections are slightly below
the worst-case scenario rates for the full sample provided in Attachment 22.
Table 7-1.

Summary of PATH Study baseline overall response rates for the predictor sample

Collection
Household Screener
Adult Extended Interview
Youth interview
Buccal cell
Urine
Blood

Unweighted
Weighted
predicted response
predicted response
rate, based on predictor rate, based on predictor
sample
sample
57.2%
57.1%
76.5%
75.7%
81.0%
81.2%
70.7%
69.0%
62.9%
61.8%
36.9%
36.9%

Projected
response
rate*
70%
85%
75%
80%
80%
65%

Worst-case
scenario
response
rate*
39.7%
58.1%
-73%
49%
39%

*Provided in the request to OMB for baseline data and biospecimen collection.

The differential weighted response rates for tobacco use status and demographic subgroups are
generally modest. (See Tables 2-1, 3-1, 3-2, and 4-1.) The largest differential weighted response rate,
10.5 percentage points, is for age for buccal cell collection; this differential rate suggests a
14

These response rates were weighted with inverse probability of selection weights.

Population Assessment of Tobacco and Health Study

heightened potential for nonresponse bias. Notably, the differential weighted response rates for
blood collection, which range from 4.0 percentage points for tobacco use status to 9.3 percentage
points for race, are consistent with those for the other collections.
As discussed in Section 1.2, the PATH Study based the interim report on a predictor sample
designed to estimate results for the entire baseline sample. Although this approach ensures a large
proportion of the cases were finalized by the time the report analyses were conducted, it does not
fully reflect the important improvements to the Study implemented months after the predictor
sample was fielded. Those changes, which are intended to boost response rates, include enhanced
field interviewer training on obtaining biospecimen consent, improved coordination of blood
collection visits, and extensive efforts to identify and schedule field work for times potential
respondents are most likely to be available. In addition, the substantial experience gained by the field
interviewers with the predictor sample and other early sample releases is expected to have increased
their effectiveness with later sample releases. For these reasons, the response rates for the predictor
sample are likely to underestimate those for the entire baseline sample.

Nonresponse Bias Analysis
Nonresponse bias analysis shows that estimates of most of the key demographic and tobacco use
variables calculated from the PATH Study predictor sample with the inverse probability of selection
weights are comparable to those produced by other national general population and health surveys.
However, the completed interviews from the predictor sample to date appear to underrepresent
single-person households relative to the 1-year 2012 ACS counts.
Based on the predictor sample, estimated percentages of demographic characteristics for adults
completing the Adult Extended Interview and for adults contributing biospecimens are not
significantly different from the 1-year 2012 ACS values for most characteristics. The estimated
percentages of adults who are Hispanic are similar to ACS values for adults responding to the Adult
Extended Interview and for adults who provide blood specimens, but Hispanics are overrepresented
among adults who provide urine and buccal cell specimens. In addition, the estimated percentage of
adults who are between 25 and 44 years old is higher for the PATH Study than for the ACS for
adult respondents as a whole and for those who provide urine and buccal cell specimens. Adults
responding to the Adult Extended Interview in the predictor sample also exhibit somewhat higher
education levels than in the ACS. These differences are not apparent among adults who provide
biospecimens, however.
47

Population Assessment of Tobacco and Health Study

When compared to national cross-sectional surveys that measure tobacco use (TUS-CPS, NHIS,
NHANES, and NSDUH), estimates of adult cigarette smoking from the PATH Study predictor
sample are roughly mid-way in the range of estimates on smoking. Hence, the analyses found no
evidence of nonresponse bias with respect to this important measure.
Estimates of demographic characteristics of youth from the predictor sample agree with 1-year 2012
ACS values for most demographic characteristics. However, Hispanic youth are overrepresented
among PATH Study respondents. (The nonresponse weight adjustments correct for this
overrepresentation.)
PATH Study estimates of the selected youth cigarette smoking measure from the predictor sample
are at the low end of estimates in comparison with national cross-sectional surveys that measure
tobacco use (NHANES, NSDUH, and NYTS). However, estimates from these surveys are from
2011 and 2012 while those from the PATH Study are from the first 5 months of the baseline wave,
September 12, 2013 to February 26, 2014, and evidence suggests the use of traditional cigarettes is
declining among youth. The difference among surveys on time period alone is not large enough to
account for the different estimates; as indicated in Section 5.2, time period is one of a number of
factors that may explain the different estimates. Estimates of cigarette smoking prevalence among
youth have large confidence intervals for all of the surveys studied.

Statistical Approach for Addressing Nonresponse
The approach used to reduce potential nonresponse bias in the PATH Study is to adjust the weights
of respondents at the household, adult, and youth levels to account for nonrespondents. Results of
applying this approach to the predictor sample indicate the nonresponse adjustments are successful
for reducing the discrepancy between the PATH Study estimates and 1-year estimates from the 2012
ACS with respect to demographic characteristics. Raked weights used for adults responding to the
Adult Extended Interview reduced differences between the PATH Study and ACS for adults
providing biospecimens as well.
Estimates of adult cigarette smoking and health insurance coverage using the IPS weights (before
nonresponse adjustment) are in line with estimates from other surveys; agreement in these estimates
is preserved using the nonresponse-adjusted weights. Weighting adjustments for youth correct for
the slight overrepresentation of Hispanics among youth in the predictor sample but have little effect
48

Population Assessment of Tobacco and Health Study

on the other demographic characteristics (i.e., IPS-weighted estimates already agreed with the ACS
values) and estimates of youth cigarette smoking.

7.2

Conclusions and Implications for Study Going Forward
Conclusions

NIDA concludes that the PATH Study baseline wave of data and biospecimen collection is yielding
scientifically defensible results that will meet study objectives. The response rates for two of the
three data collections, Household Screener and Adult Extended Interview, are lower than projected.
However, nonresponse bias analysis found the characteristics of the respondents are generally in line
with the 1-year estimates from the 2012 ACS. Estimates of the cigarette smoking rate among adults
based on the predictor sample are within the range of rates found in other national health studies.
Moreover, when the predictor sample estimates were adjusted for nonresponse using the raked
weights, they more closely approximated the ACS estimates and the adult smoking rates remained
essentially the same.
The response rate for the third data collection, Youth Interview, is higher than projected. For this
collection, the nonresponse bias analysis also found the characteristics of respondents to be
generally consistent with the 1-year estimates from the 2012 ACS. The ever-tried-smoking rate for
youth based on the predictor sample is at the low end of the range of rates found by other national
health studies. However, when the predictor sample estimates were adjusted for nonresponse, they
more closely approximated the 2012 ACS estimates and the ever-tried-smoking rates for youth
found by other national studies.
The response rates for the three biospecimen collections are lower than projected, and the response
rates for the buccal cell and blood collections are slightly below the worst–case scenario rates.
Nonetheless, nonresponse bias analysis found the characteristics of the respondents to be generally
in line with estimates from the 1-year 2012 ACS. When the predictor sample estimates were adjusted
for nonresponse, they more closely approximated the ACS estimates.
Due to the limited number of predictor sample biospecimens that have been analyzed to date, this
report does not include a comparison of predictor sample biospecimen results (e.g., on nicotine
metabolites) with those from other national studies that collect survey data on smoking in

Population Assessment of Tobacco and Health Study

combination with biospecimens. Analyses of biospecimens are continuing, however, with plans for
these and other analyses in the near future for the predictor sample biospecimens and eventually, for
the full baseline sample.

Implications for Study Going Forward
The implications of these findings for the PATH Study are that ongoing efforts to increase the
response rates should be explored and implemented; adjustments to the sampling strategy and/or
target yields should be considered to compensate for the lower response rates achieved to date; and
the approach for adjusting the IPS weights to account for nonresponse should be continued and
refined for the full sample. Each of these three courses of action is further discussed below.
First, the PATH Study will seek to increase its response rates during the baseline wave. As
mentioned in Section 7.1, the Study has been implementing steps intended to improve its response
rates. Some of these have taken place after the 5th month of the baseline, however, and are not fully
reflected in the predictor sample results. The PATH Study is continuously seeking ways to improve
its response rates in the baseline. In addition, as discussed in Supporting Statement B of the PATH
Study's non-substantive change request for the baseline wave, the Study has developed steps to help
it achieve high response rates in its followup waves. These involve maintaining contact with baseline
respondents, tracing respondents for whom contact is lost, and reaching out to engage individuals
who age into the youth cohort or adult cohort.
Second, the PATH Study is planning to adjust its sampling strategy to compensate for the lower
response rates achieved to date and any revisions to target baseline sample sizes. This strategy may
include releasing additional addresses to the field during the field period and increasing the sampling
rates for adults at the household and individual screening phases. As needed, the Study will adjust its
analytic plans to account for potentially smaller sample yields than planned, for example, by
combining some subgroups.
Third, once the baseline wave has ended, the PATH Study plans to continue its approach to
adjusting the IPS weights to account for nonresponse. Doing so for the interim report highlighted
the usefulness of this approach in reducing potential nonresponse bias. The Study will continue to
refine and improve the weighting procedures as more data become available. The Study will also
repeat the nonresponse bias analysis that was conducted for this report. When performed with the
full sample, the nonresponse bias analysis will serve the same purposes as in this report: to provide
50

Population Assessment of Tobacco and Health Study

measures of the Study’s validity and contribute to refining the weighting procedures for the full
sample.

Population Assessment of Tobacco and Health Study

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http://www.fcsm.gov/05papers/Wang_Aldworth_etal_VIB.pdf.

Population Assessment of Tobacco and Health Study

Appendix A
Cigarette Smoking Questions on the PATH Study
and Other Surveys
Table A-1 lists the questions used to ask about current smoking status of adults in the PATH Study
and in the surveys used for comparison and describes the populations included in the estimates from
those surveys.

A-1

Table A-1.

Question used to define “current smoking” in the PATH Study, TUS-CPS, NHIS, NHANES, and NSDUH

PATH Study
TUS-CPS
NHIS
Question to define current smoking (answers defining current smoking given in parentheses)
“Have you ever smoked a cigarette, "Have you smoked at
"Have you smoked at least 100
even one or two puffs?” (yes) and
least 100 cigarettes in
cigarettes in your ENTIRE LIFE?"
“Do you now smoke cigarettes
your entire life?" (yes)
(yes) and "Do you NOW smoke
every day, some days, or not at
and "Do you now smoke cigarettes every day, some days
all?" (every day or some days) and cigarettes every day,
or not at all?" (every day or some
“How many cigarettes have you
some days, or not at all?" days)
smoked in your entire life? A pack
(every day or some days) (SMQEV, SMKNOW)
usually has 20 cigarettes in it.” (100 (PEA1, PEA3)
or more cigarettes (5 packs or
more))

Proxy responses allowed
No

NSDUH
*
(modified definition)

"{Have you/Has SP}
smoked at least 100
cigarettes in
{your/his/her} entire
life?" (yes) and "{Do
you/Does SP} now
smoke cigarettes every
day, some days or not
at all?" (every day or
some days)
(SMQ020, SMQ040)

“Have you ever
smoked part or all of a
cigarette?” (yes) and
“During the past 30
days, have you
smoked part or all of a
cigarette?” (yes)

“Have you ever smoked
part or all of a cigarette?”
(yes) and “During the past
30 days, have you smoked
part or all of a cigarette?”
(yes) and “Have you
smoked at least 100
cigarettes in your entire
life?” (yes)

20+

18+

Includes only civilian,
non-institutionalized
population.

Includes only civilian
Includes only civilian,
noninstitutionalized population.
non-institutionalized
Several segments of the
population.
population excluded, such as:
patients in long-term care
facilities; persons on active duty
with the Armed Forces; persons
incarcerated in the prison system;
and U.S. nationals living in foreign
countries.

Includes only civilian,
non-institutionalized
population. Excludes
homeless persons who
do not use shelters,
military personnel on
active duty, and
residents of
institutional group
quarters.

Yes

Yes, for individuals physically or
No
mentally incapable of responding
*
(468 cases in 2012)

*The modified definition is given in Ryan et al. (2012).
** Proxies are allowed if 4th callback, the person will not return before closeout, or the household is getting irritated. See http://appliedresearch.cancer.gov/studies/tuscps/surveys/tuscps_english_2010.pdf, p3.

Population Assessment of Tobacco and Health Study

A-2

Age range included in estimate
18+
Exclusions from population
Includes only civilian, noninstitutionalized population.
Excludes residents of group
quarters, active military.

NSDUH (original
definition)

NHANES

Population Assessment of Tobacco and Health Study

Note that although the questions used to define current cigarette smoking are similar among the
surveys, small differences could have an effect on the answers given. In the PATH Study, the
question used to establish whether an adult has smoked at least 100 cigarettes in his or her lifetime
has closed response categories:
1.

1 or more puffs but never a whole cigarette

1 to 10 cigarettes (about ½ pack total)

11 to 20 cigarettes (about ½ pack to 1 pack)

21 to 50 cigarettes (more than 1 pack but less than 3 packs)

51 to 99 (more than 2 ½ packs but less than 5 packs)

100 or more cigarettes (5 packs or more)

In TUS-CPS, NH S, and NHANES, however, the question “Have you smoked at least 100
cigarettes in your entire life?” calls for a yes/no response.
The positioning of the questions also differs among the surveys. In the PATH Study, the cigarette
smoking questions are near the beginning of the adult questionnaire, and the respondent knows that
the questionnaire is about tobacco use behaviors. In TUS-CPS, the smoking questions are near the
beginning of the adult questionnaire on tobacco, but the survey is administered as part of the CPS.
In NHIS, the smoking questions follow a long series of questions on health problems (breathing
problems, diabetes, hernias, hemorrhoids, etc.). These question contexts may be associated with
differences in responses.
Table A-2 lists the questions used to define youth cigarette smoking in the PATH Study, NHANES,
NSDUH, and NYTS.

A-3

Table A-2.

Questions used for youth cigarette smoking in the PATH Study, NHANES, NSDUH, and NYTS
PATH Study

NHANES

NSDUH

Question to define ever tried cigarette smoking (answers defining ever tried cigarette smoking given in parentheses)
“Have you ever tried cigarette smoking,
“About how many cigarettes have you smoked in your
CG01 Have you ever smoked part or
even one or two puffs?” (yes)
entire life?” (SMQ621, values of 2-8 (more than a puff
all of a cigarette? (yes)
to 100 or more cigarettes))

NYTS
Have you ever tried cigarette
smoking, even one or two
puffs? (Qn7 value of 1, Yes)

I have never smoked, not even a puff (1), 1 or more
puffs but never a whole cigarette (2),

Exclusions from population
Residents of group quarters

CG05 [IF CG01 = 1 OR CGREF1 = 1]
Now think about the past 30 days –
that is, from [DATEFILL] up to and
including today. During the past 30
days, have you smoked part or all of
a cigarette?

During the past 30 days, on
how many days did you
smoke cigarettes? (Qn13
values of 2 through 7)

12-17

12-17 year old students in
public or private schools

Includes only the U.S. civilian, noninstitutionalized
population.

Includes only the U.S. civilian,
noninstitutionalized population.
Excludes homeless persons who do
not use shelters, military personnel
on active duty, and residents of
institutional group quarters.

Only includes youth who
attend either public or private
schools.

Those missing SMQ621 values are excluded from the
estimates.
Those with SMQ621=1, 2, 77 or 99 (never smoked, less
than 1 cigarette, RF, DK) had SMD640 recoded to 0 (0
cigarette smoked in past 30 days) due to skip pattern.

The estimates are given in
Center for Behavioral Health
Statistics and Quality (2013a, b)
gives estimates and the standard
errors of the estimates.

The survey is administered by
teachers in the classroom
setting.

Other comments

Population Assessment of Tobacco and Health Study

A-4

1 cigarette (3),
16 to 25 cigarettes (6),
2 to 5 cigarettes (4),
26 to 99 cigarettes (7),
6 to 15 cigarettes (5),
100 or more cigarettes (8)
Questions for determining whether have smoked in past 30 days
“Have you ever tried cigarette smoking,
“During the past 30 days, on how many days did you
even one or two puffs?” (yes) and “When smoke cigarettes?” (SMQ640, Recoded to SMD641 in
was the last time you smoked a
SMQ_G file, number of day smoked, values of 1
cigarette, even one or two puffs?” (Earlier through 30)
today, Not today but sometime in the
past 7 days, Not in the past 7 days but
sometime in the past 30 days)
Ages of youth in survey
12-17
12-17

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