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SURVEY OF INCOME AND PROGRAM PARTICIPATION (SIPP)
Purpose
The Survey of Income and program participation (SIPP) collects “source and amount of income, labor force information, program participation and eligibility data, and general demographic characteristics to measure the effectiveness of existing federal, state, and local programs; to estimate future costs and coverage for government programs, such as food stamps; and to provide improved statistics on the distribution of income in the country”
(http://www.sipp.census.gov/sipp/overview.html).
Agencies/Institutions
The SIPP is sponsored by the U.S. Census Bureau and administered by the Demographics Survey Division of the U.S. Census Bureau. The Department of Health, Education, and Welfare developed the forerunner to the SIPP, the Income Survey Development Program (ISDP), and participated in early design work for the SIPP itself.
Research/Survey Design
“SIPP produces national-level estimates for the U.S. resident population and subgroups. Although the SIPP design allows for both longitudinal and cross-sectional data analysis, SIPP is meant primarily to support longitudinal studies. SIPP’s longitudinal features allow the analysis of selected dynamic characteristics of the population, such as changes in income, eligibility for and participation in transfer programs, household and family composition, labor force behavior, and other associated events” (http://www.sipp.census.gov/sipp/analytic.html).
The SIPP uses a multistage-stratified sample of the U.S. civilian noninstitutionalized population. The first stage involves selecting primary sampling units (PSUs) made up of one or more contiguous counties; the second stage samples addresses within the selected PSUs.
“All household members 15 years old and over are interviewed by self-response, if possible; proxy response is permitted when household members are not available for interviewing” (http://www.sipp.census.gov/sipp/overview.html). Proxy interviewing occurs more often than the Census Bureau would like.
For more information:
http://www.sipp.census.gov/sipp/
Date(s)/Periodicity
In February 2001, a 3-year 2001 panel comprising 36,700 sample units (households) was introduced. These households will be interviewed in interviewing periods, called waves, from February 2001 through January 2004. The SIPP uses a 4-month recall period. Approximately the same number of interviews are conducted in each month of the 4-month period for each wave.
For more information:
http://www.sipp.census.gov/sipp/
Population/Sample
The SIPP is a continual series of national panels, with sample size ranging from approximately 14,000 to 36,700 interviewed households. Each panel lasts from 2.5 to 4 years. The SIPP sample is a multistage-stratified sample of the U.S. civilian noninstitutionalized population. From 1984 to 1993, a panel of households was introduced each year in February. The 2001 panel comprises 36,700 households, which will be interviewed nine times from February 2001 through January 2004. The 2001 panel SIPP interviews use a computer-assisted interview (CAPI) on a laptop computer. Unlike the CPS, the SIPP excludes people living in military barracks from the sample. A survey is completed in Wave 1 for each member of the household age 15 or older; in succeeding waves, each of these original sample members is surveyed as well as all current residents 15 and older of the households in which original sample members currently live.
“The rate of sample loss in SIPP generally declines from one wave to the next. The total number of sample members lost, also known as total sample attrition, always increases over time. Wave 1 nonresponse rates for SIPP have been about 7.7 percent. There is usually a sizable sample loss at Wave 2, with a lower rate of additional attrition occurring at each subsequent wave. Prior to the 1992 Panel, SIPP lost roughly 20 percent of the original sample by the panel’s completion. The sample loss rate for the 1996 Panel was 35.5 percent by the end of the 12th, or final, wave”
(http://www.sipp.census.gov/sipp/types_non.html).
Low-income housing units were oversampled in the 1990, 1996, and 2001 panels. For more information: http://www.sipp.census.gov/sipp/
Content Covered
The SIPP collects two categories of information: core and topical. The core content includes questions asked at every interview and covers demographic characteristics; labor force participation; program participation; amounts and types of earned and unearned income received, including transfer payments; noncash benefits from various programs; asset ownership; and private health insurance. Most core data are measured monthly, although a few core items are measured only once every 4 months, on the interview date.
Topical questions produce in-depth information on specific social and economic characteristics and personal histories, such as assets and liabilities, school enrollment, marital history, fertility, migration, disability, work history, child care, child support, wealth, program eligibility, taxes, and annual income. They are asked less often, are often found in topical modules that usually follow the core content, and usually collect information on events in the past or characteristics that change slowly.
Availability of Data for Public Use
Data are periodically released in cross-sectional, topical module, and longitudinal reports. Public use files contain the core data on income recipiency and program participation. These files are available for all waves of the 1984 through 1996 panels, and Waves 1 through 4 longitudinal of the 2001 panel. Topical module files containing core and topical module data also are available for these panels for 1984 through 1988, and 1990 through the 1996 panels. Longitudinal files are also available for the 1984-1996 panels. For access to the data files, go to http://www.sipp.census.gov/sipp/access.html. More information is available at http://www.sipp.census.gov/sipp/public.html.
The SIPP website is http://www.sipp.census.gov/sipp/. The core questionnaire for the 2001 panel (and core and topical questionnaires for the 1993 and 1996 panels) is available at http://www.sipp.census.gov/sipp/questionnaires.html. (Wave 2 core questionnaires are also used in succeeding waves of the panel.) For questionnaires for the topical modules of the 2001 panel that have been completed so far, see http://www.sipp.census.gov/sipp/top_mod/2001/top_mod_sched.html.
Reference List for Users’ Guide, Codebooks, Methodology Report(s)
The 2001 SIPP Users’ Guide is available at http://www.sipp.census.gov/sipp/usrguide/sipp2001.pdf.
Technical documentation for the various data files of the 1993 and 1996 panels is available at http://www.census.gov/apsd/techdoc/sipp/sipp.html; the documentation for each file includes a data dictionary and source and accuracy statement.
For data quality information about all the SIPP panels, see http://www.sipp.census.gov/sipp/source.html.
A searchable SIPP bibliography containing both methodological papers and reports using SIPP data has also been prepared; it is available at http://www.sipp.census.gov/sipp/aboutbib.html.
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