Attachment Q - Response Rates in the CE

Response Rates in the
Consumer Expenditure
Survey

Sylvia A. Johnson-Herring
and Sharon Krieger

Sylvia A. Johnson-Herring is a mathematical
statistician in the Division of Price Statistical
Methods, Branch of Consumer Expenditure
Surveys, U.S. Bureau of Labor Statistics.
Sharon Krieger is a mathematical statistician in
the Division of Price Statistical Methods, Branch
of Consumer Expenditure Surveys, U.S. Bureau
of Labor Statistics.

R

esponse rates are one of the
most important indicators of a
survey’s quality. It is important
to monitor survey participation and to
monitor response rates because nonresponse can introduce bias into any
survey’s published estimates. When a
survey’s responders and nonresponders
differ in terms of the characteristic being measured, great care must be taken
to produce accurate estimates for the
population as a whole. Although most
surveys have procedures to adjust for
nonresponse, any imperfection in them
is magnified when response rates decline. Therefore, it is important to
monitor response rates and keep them
as high as possible.
This article describes how the Consumer Expenditure Survey (CE) categorizes the outcomes of visits to survey households in terms of response
and nonresponse, and explains how the
U.S. Bureau of Labor Statistics (BLS)
calculates the CE response rates.
Selection of households
The CE selects a representative sample
of households from across the Nation
to find out how Americans spend their
money. Specific households to visit are
drawn from the decennial census 100percent-detail file, which is a complete
list of addresses of American households. Independent samples of households are selected for the Interview and
Diary components of the CE.

20 Consumer Expenditure Survey Anthology, 2008

Field representatives visit households in each survey’s sample to collect
data. For the Interview survey, people
living at an address answer the survey
questions five times, with the interviews conducted at 3-month intervals
for 5 quarters. For the Diary Survey,
people living at an address answer the
survey questions two times, keeping
a diary for two 1-week periods. Gaining cooperation at each household is
important because each household in
the sample represents many American
households.
Nonresponse types and
outcome codes
Like any survey, the CE does not get
responses from every household in its
sample. At most addresses, a household member participates, giving a
“completed interview.” However, at
some addresses, the survey’s field representative finds an occupied housing
unit but either is unable to contact an
eligible household member or is unable to convince a reluctant household
member to participate in the survey.
At still other addresses, the housing
unit is unoccupied, or the structure is
nonresidential or otherwise not eligible
to participate in the survey. Such cases
are called “nonresponders.”
Field representatives assign outcome
codes to each address that they visit.
Multiple visits to an address may be
necessary before a final outcome code

can be assigned. Sometimes, multiple
visits are made in an attempt to convince reluctant households to respond
to the survey; other times, it takes more
than one visit before a field representative actually contacts an eligible household member. When field representatives make multiple visits and are still
unable to find anyone home, they may
obtain information from neighbors or
people in the area to verify the status
of the housing unit. Sample households
are assigned a separate outcome code
for each quarter in the Interview survey and for each week in the Diary
survey. Although field representatives
assign the outcome code, BLS may
make some changes later based on criteria that measure the completeness of
respondents’ reporting of household income and expenditures.
Field representatives can select from
more than 30 different outcome codes
to describe the nonresponse situation
that they find at an address. These outcome codes are categorized as Types
A, B, and C nonresponses. Some common outcome codes for Type A nonresponses are as follows: Temporarily
absent; No one home (unable to contact); Refused—hostile respondent;
Refused—time-related excuses; and
Refused—language problems. Some
common outcome codes for Type B
nonresponses are: Occupied by persons
with usual residency elsewhere; Vacant
for rent; Vacant for sale; and Unit under
construction. Some common outcome
codes for Type C nonresponses are:
Dwelling demolished; House or trailer
moved; Dwelling condemned; and Located on military base or post.
Two essential concepts when classifying sample addresses in terms of response and nonresponse are “eligible”
and “in scope.” Completed interviews
and Types A and B nonresponders are
all “in scope,” while Type C nonresponders are “out of scope” for the CE.
In scope refers to addresses that have
residential housing units. Out-of-scope
addresses are generally nonresidential.
An address is eligible to participate
in the survey if the residential housing
unit at the address is occupied by its

usual residents; otherwise, it is not eligible. Completed interviews and Type
A nonresponders are eligible, but Types
B and C nonresponders are not eligible.
Only eligible addresses are used in the
response rate calculations.
Type A nonresponders are both in
scope and eligible, because their housing units are occupied by the usual
residents. Type B nonresponders are
in scope, but they are not eligible, because the housing units are not occupied or the housing units are occupied
solely by persons whose usual place of
residence is elsewhere. Interviews are
not possible for Type C nonresponders,
because these cases are out of scope
and permanently not eligible to participate in the CE; empty lots or buildings
used for nonresidential purposes fall
into this category.
In summary, results of visits to the
sample addresses are divided into four
main categories:
• Completed Interviews (eligible
cases that are interviewed—in
scope)
• Type A nonresponses (eligible
cases that are not interviewed—
in scope)
• Type B nonresponses (cases that
are not eligible for interview—in
scope)
• Type C nonresponses (cases that
are not eligible for interview—
out of scope)
Response rates
The CE program defines the response
rate as the percent of eligible house-

holds that actually are interviewed
for each survey. Types B and C nonresponders are not part of the response
rate, because they are not eligible for
the survey.
Response rates are reported separately for the Interview and Diary components of the CE. When calculating a
response rate for the Interview survey,
BLS generally uses outcome information only from the second through fifth
interviews. Information from the first
interview is used only for “bounding”
purposes, which address a common
problem in which survey respondents
tend to report expenditures to have
been made more recently than they
were actually made. When calculating
a response rate for the Diary survey,
BLS uses outcome information from
the two 1-week periods a household is
in the sample.
The sample size and response status
for housing units “designated” for the
Interview survey in 2004 and 2005 are
shown in table 1. The CE counts each
of the four “nonbounding” interviews
at a household (interviews 2–5) separately when reporting the number of
housing units designated for the Interview survey; in other words, interviews
2–5 at one household generally represent four housing units designated for
the survey. In 2005, there were 49,242
housing units designated for the Interview Survey. Field representatives occasionally find more than one housing
unit at the addresses they visit, so the
number of housing units designated is
slightly more than the number of addresses selected for the sample. Those
49,242 housing units designated for the
survey contained 39,988 eligible units
and 9,254 ineligible units. The 39,988

Table 1. Analysis of response in the CE Interview Survey, 2004 and 2005
Sample unit
Housing units designated for the survey
Less: Type B or C nonresponses
Equals: Eligible units
Less: Type A nonresponses
Equals: Interview units
Percent of eligible units interviewed

2004

2005

50,509

49,242

9,626

9,254

40,883

39,988

9,798

10,184

31,085

29,804

76.0

74.5

Consumer Expenditure Survey Anthology, 2008 21

eligible units produced 29,804 completed interviews, yielding a response
rate of 74.5 percent (29,804/39,988=
0.745).
In 2005, the CE’s sample design
was changed. The list of addresses
from which the sample is drawn was
updated by replacing the 1990 decennial census 100-percent-detail file with
the 2000 decennial census 100-percentdetail file. Under special procedures,
all households selected from the 2000
Census-based sample in January 2005
were treated as first interviews during
the transition. Hence, as shown in table 1, the number of Interview survey

housing units designated in 2005 is less
than normally would be expected.
The sample size and response status for housing units “designated” for
the Diary survey in 2004 and 2005 are
shown in table 2. The CE counts each
of the two 1-week diary periods at a
household separately when reporting
the number of housing units designated
for the Diary survey. In 2005, there
were 26,054 housing units designated
for the Diary survey. (The two diaries
are counted as separate interviews.)
Field representatives occasionally find
more than one housing unit at the addresses they visit, so the number of

Table 2. Analysis of response in the CE Diary Survey, 2004 and 2005
Sample unit
Housing units designated for the survey
Less: Type B or C nonresponses
Equals: Eligible units
Less: Type A nonresponses
Equals: Interview units
Percent of eligible units interviewed

22 Consumer Expenditure Survey Anthology, 2008

2004

2005

27,385

26,054

5,746

4,745

21,639

21,309

6,722

6,183

14,917

15,126

68.9

71.0

housing units designated is slightly
more than the number of addresses
selected for the sample. Those 26,054
housing units designated for the survey contained 21,309 eligible units and
4,745 ineligible units. The 21,309 eligible units produced 15,126 completed
interviews, yielding a response rate of
71.0 percent (15,126/21,309=0.710).
For both the Interview and Diary
surveys, the number of Types B and C
nonresponses decreased from 2004 to
2005. This decrease can be attributed
to the more up-to-date list of addresses
used to select the sample in 2005.
Conclusion
The CE collects expenditure data from
a representative sample of American
households. Like any survey, the CE
does not get responses from every
household in its sample. This article
has described how the CE categorizes
the outcomes of visits to survey households and how it calculates response
rates. It is important to monitor response rates and to keep them as high
as possible in order to minimize the
amount of bias that can be introduced
into the survey estimates.