Survey of Income and Program Participation

SIPP uses a complex sample design, rather than a simple random sample, to determine which households are interviewed. The 2018 SIPP sampled 53,660 designated Living Quarters (LQs), which yielded 44,870 eligible LQs. Of those eligible LQs, 26,215 households were interviewed between February and July 2018, resulting in 64,191 person interviews and a response rate of 58.4 percent.

The Census Bureau employs a two-stage sample design to select the SIPP sample. The two stages are (1) selection of primary sampling units (PSUs) and (2) selection of address units within sample PSUs. Census Bureau interviewers follow an established procedure to identify sample members within the selected address units. This complex sample design has important implications for the estimation of standard errors. Because the SIPP design is not a simple random sample, the standard errors reported by most off- the-shelf statistical software will underestimate the true standard errors of estimates from SIPP. The SIPP sample universe is the civilian, noninstitutionalized population of the United States. The sampling universe is based on addresses from multiple sources – chiefly the 2010 Decennial Census and contains approximately 304.4 million individuals. SIPP samples housing units from the current Master Address File (MAF), which is maintained by the U.S. Census Bureau and is the source of addresses for the American Community Survey, other demographic surveys, and the decennial census. The MAF is updated using the U.S. Postal Service’s Delivery Sequence File and various automated, clerical, and field operations. The 2018 SIPP sample is a multistage, stratified sample of about 53,000 LQs from 686 sample areas designed to represent the civilian, noninstitutionalized population of the U.S.

• Mixed or multi modes
• Survey (self- or interviewer-administered)

There are three basic elements contained in the overall design of the survey content. The control card is used to record basic social and demographic characteristics for each person in the household at the time of the initial interview. The second major element of the survey content is the core portion of the questionnaire. The core questions are repeated at each interview and cover labor force activity, the types and amounts of income received during the four- month reference period, and participation status in various programs. The third major element is the various supplements or topical modules that will be included during selected household visits. A list of topical modules includes work history, health characteristics (including disability), assets and liabilities, pension plan coverage, housing characteristics, child care, child support agreements, support for non-household members, program participation history, reasons for not working, calendar year income and benefits, taxes, and education and training.

The SIPP survey design is a continuous series of national panels. The duration of each panel ranges from 2.5-4 years.

The COVID-19 pandemic presented data collection challenges resulting in under-representation of certain populations in some surveys. This non-response bias may impact the ability to conduct certain research. Additional information for the SIPP can be found at https://www.census.gov/programs-surveys/sipp/data/datasets/2020-data/2020.html and https://www.census.gov/programs-surveys/sipp/tech-documentation/user-notes/2020-usernotes/covid-coll-impact-unit-nonresp.html.

To assign PIKs to respondents, request the BOC Consolidated PIK Crosswalk Survey of Income and Program Participation (SIPP) (ID# 417)

• Protected identification key (PIK)