Current Population Survey Design and Methodology - Census Bureau

Chapter 11.
Current Population Survey Supplemental Inquiries
INTRODUCTION
In addition to providing data on the labor force status of
the population, the Current Population Survey (CPS) is
used to collect data for a variety of studies on the entire
U.S. population and specific population subsets. These
studies keep the nation informed of the economic and
social well-being of its people and are used by federal and
state agencies, private foundations, and other organizations.
Supplemental inquiries take advantage of several
special features of the CPS: large sample size and general
purpose design; highly skilled, experienced interviewing
and field staff; and generalized processing systems that
can easily accommodate the inclusion of additional questions.
Some CPS supplemental inquiries are conducted annually,
others every other year, and still others on a one-time
basis. The frequency and recurrence of a supplement
depend on what best meets the needs of the supplement’s
sponsor. In addition, any supplemental inquiry must meet
strict criteria discussed in the next section.
Producing supplemental data from the CPS involves more
than just including additional questions. Separate data
processing is required to edit responses for consistency
and to impute missing values. An additional weighting
method is often necessary because the supplement targets
a different universe from that of the basic CPS. A supplement
can also engender a different level of response or
cooperation from respondents.
CRITERIA FOR SUPPLEMENTAL INQUIRIES
A number of criteria to determine the acceptability of
undertaking supplements for federal agencies or other
sponsors have been developed and refined over the years
by the U.S. Census Bureau, in consultation with the U.S.
Bureau of Labor Statistics (BLS).
The staff of the Census Bureau, working with the sponsoring
agency, develops the survey design, including the
methodology, questionnaires, pretesting options, interviewer
instructions and processing requirements. The Census
Bureau provides a written description of the statistical
properties associated with each supplement. The same
standards of quality that apply to the basic CPS apply to
the supplements.
The following criteria are considered before undertaking a
supplement:
Current Population Survey TP66
U.S. Bureau of Labor Statistics and U.S. Census Bureau
1. The subject matter of the inquiry must be in the public
interest.
2. The inquiry must not have an adverse effect on the
CPS or other Census Bureau programs. The questions
must not cause respondents to question the importance
of the survey and result in losses of response or
quality. It is essential that the image of the Census
Bureau as the objective fact finder for the nation is not
damaged. Other important functions of the Census
Bureau, such as the decennial censuses or the economic
censuses, must not be affected in terms of
quality or response rates or in congressional acceptance
and approval of these programs.
3. The subject matter must be compatible with the basic
CPS survey and not introduce a concept that could
affect the accuracy of responses to the basic CPS information.
For example, a series of questions incorporating
a revised labor force concept that could inadvertently
affect responses to the standard labor force
items would not be allowed.
4. The inquiry must not slow down the work of the basic
survey or impose a response burden that may affect
future participation in the basic CPS. In general, the
supplemental inquiry must not add more than 10 minutes
of interview time per respondent or 25 minutes
per household. Competing requirements for the use of
Census Bureau staff or facilities that arise in dealing
with a supplemental inquiry are resolved by giving the
basic CPS first priority. The Census Bureau will not
jeopardize the schedule for completing the CPS or
other Census Bureau work to favor completing a
supplemental inquiry within a specified time frame.
5. The subject matter must not be sensitive. This criterion
is imprecise, and its interpretation has changed
over time. For example, the subject of birth expectations,
once considered sensitive, has been included as
a CPS supplemental inquiry.
6. It must be possible to meet the objectives of the
inquiry through the survey method. That is, it must be
possible to translate the supplemental survey’s objectives
into meaningful questions, and the respondent
must be able to supply the information required to
answer the questions.
7. If the supplemental information is to be collected during
the CPS interview, the inquiry must be suitable for
the personal visit/telephone procedures used in the
CPS.
Current Population Survey Supplemental Inquiries 11–1