SPD OverviewPrecursors of the SPD
Overview of SPD
The SPD Universe
The SPD Sample
The SPD Content
The SPD Data Products
Comparison to Other Surveys
During the Great Depression, the Enumerative Check Census (taken as a part of the 1937 unemployment registration) was the first attempt to estimate unemployment on a nationwide basis using probability sampling. There had been earlier attempts to estimate the number of unemployed, ranging from guesses to enumerative counts. Experience with the Enumerative Check Census, and research performed by the Work Projects Administration (WPA), led to the creation in 1940 of the Sample Survey of Unemployment. Responsibility for that survey was transferred from WPA to the Bureau of the Census in 1942, and the name of the survey was changed to the Current Population Survey (CPS). Since 1948, the CPS has included supplemental questions (at first, in April; later, in March) on income received in the previous calendar year.
In April 1973, the Office of Management and Budget's Statistical Policy Division asked the Interagency Committee on Income Distribution and the Interagency Committee on Poverty Statistics to conduct a thorough review of federal income and poverty statistics (Fisher 1992). Subcommittees were formed to study the following topics: updating the poverty threshold, improving the measurement of cash income, and measuring noncash income. One of the recommendations made by the Subcommittee on Measurement of Cash Income was for a separate income survey that would encompass items not covered by the March supplement of the CPS–to collect better money (and nonmoney) income data.
To address inadequacies in available survey data, the U.S. Department of Health, Education, and Welfare established the Income Survey Development Program (ISDP). The goal of the ISDP was to plan a recurring survey of income, assets, program eligibility, and participation. The ISDP researched and resolved a series of technical and operational issues before adopting a final design framework for a new survey, which became fully operational in 1983. That survey became the Survey of Income and Program Participation (SIPP).
The original design of the SIPP called for a nationally representative sample of individuals (15 years of age and older), to be selected in households in the civilian noninstitutionalized population. Those individuals, along with others who subsequently lived with them, were to be interviewed once every four months over a 32-month period. The first sample, the 1984 Panel, began interviews in October 1983 and finished in July 1986. The second sample, the 1985 Panel, began interviews in February 1985 and finished in August 1987. Subsequent panels (through 1993) began interviews in February of the calendar year. The 1993 panel finished interviewing in January 1996. There were no panels in 1994 and 1995, and the program was redesigned for 1996.
In early 1993, a group of Census Bureau scientists began discussions about developing an extended SIPP panel, to follow respondents for a period longer than four years. By the fall of 1994, rough goals for the survey were set: to provide information on actual and potential program participants over a ten-year period and to examine the consequences of program participation on the well-being of recipients, their families, and their children. To deal with the likelihood of major welfare reform legislation (and with funding from the Departments of Agriculture and Health and Human Services), by the beginning of 1995 a Census Bureau workgroup had assembled content material for the survey–mostly from the content of the SIPP, with additional material submitted by various experts on children's research issues. Although a pretest of the instrument was planned for the spring of 1996 (with implementation planned for the spring of 1997), a lack of funding for the program resulted in its being sidelined.
In August 1996, the U.S. Congress enacted legislation to reform the national welfare system. That legislation, the "Personal Responsibility and Work Opportunity Reconciliation Act of 1996" (Public Law 104-193), specified (in Section 414) that the Census Bureau continue to collect data on the 1992 and 1993 panels of the SIPP. The legislation directs the Census Bureau to pay particular attention to the issues of out-of-wedlock births, welfare dependency, the beginning and end of welfare spells, the causes of repeat welfare spells, and the status of children in the surveyed households. In response to that legislation, the Census Bureau created the Survey of Program Dynamics (SPD).Top
Overview of the SPD
The Survey of Program Dynamics is a longitudinal, demographic survey designed to collect data on the economic, household, and social characteristics of a nationally representative sample of the U.S. population over time. The primary goals of the SPD are to provide information on spells of actual and potential program participation (over a ten-year period), to examine the causes of program participation and its long-term consequences (on recipients and their families), and to monitor the possible long-term changes (for individuals) that result from implementing welfare reform.
To provide policy makers the data necessary to assess the effects of national welfare reforms (how these reforms interact with each other, and with employment, income, and family circumstances), the SPD was designed to create a longitudinal database spanning a ten-year period and consisting of three components: information collected in the 1992 and 1993 panels of the SIPP; information collected in 1997 using a modified version of the March CPS; and information collected from 1998 to 2002 using the SPD instrument.
All SIPP people interviewed in the first wave of the 1992 and 1993 panels, and still being interviewed at the end of their panel, were eligible for the SPD sample. The 1997 SPD was a "bridge" between the earlier SIPP interviews and the new SPD survey, and used a modified version of the March CPS questionnaire (which includes the annual income supplement). The CPS annual income supplement obtains data for the previous calendar year on topics such as work experience, earnings, program participation, income, and health insurance.
The SPD questionnaire developed for 1998 through 2002 covers a wider variety of topics, to measure the impact of welfare reform legislation on previous program participants, and to compare their situations with those of the rest of the country.Top
Analysts will be able to use the SPD longitudinal database to address all of the following research objectives: determine the types of jobs that previous welfare recipients are getting (and the types of employers hiring them); determine if their new employers are providing benefits (and how these benefits compared to those they received while on welfare); determine whether previous recipients used any type of training to obtain a job, whether they stay at the first job obtained after leaving the welfare system, or if they move on to a new job; measure the economic impact of welfare reform directly (by comparing information that shows whether a family's economic situation is better or worse after welfare reform, and whether those who have several jobs over a period of time make more money than those who stay at one job); measure how long people are unemployed between jobs, and how children are affected by parent's employment; estimate how long individuals go without health insurance and examine such lapses in coverage; illustrate the relationship between work training, education, employment and earnings; show the effect of the welfare reform measures on people with disabilities, making it possible to relate disability status to income, employment, health insurance coverage and receipt or discontinuance of program benefits; and, monitor the effects of welfare reform on the nation.Top
The SPD Universe
The SPD universe consists of people who resided in the United States (except those living in institutions, such as prisons and nursing homes or entire military households) in March 1992 or March 1993. The universe is represented by original sample members from the 1992 and 1993 Survey of Income and Program Participation (SIPP) panels, except those who were subsampled out because of cost constraints or who left the survey universe before the 1998 interview. This population includes people (including children) living in group quarters, such as dormitories, rooming houses, and religious group dwellings. It does not include crew members of merchant vessels, Armed Forces personnel living in military barracks, and institutionalized people, such as correctional facility inmates and nursing home residents. In addition, United States citizens residing abroad were not eligible to be in the survey. Foreign visitors who work or attend school in this country and their families were eligible. All others were not eligible to be in the survey. With the exceptions noted above, people who were at least 15 years of age at the time of the interview were eligible to be asked income and job experience.Top
The SPD Sample
Based on their inclusion in the first and last waves of the 1992 and 1993 SIPP panels, there were 34,609 households eligible for the SPD. For 1998, the SPD sample was reduced (for budgetary reasons) to 19,129 households. The table below summarizes the sample sizes by year, along with information on the numbers of eligible and interviewed households.
|Sample||Eligible Households||Sample Households||Interviewed Households|
The SPD Content
The SPD longitudinal database will contain data collected using three different survey instruments: the 1992/1993 SIPP paper instruments, used to collect data for calendar years 1992, 1993, and 1994; a modified March CPS computer-assisted personal interviewing (CAPI) instrument, used to collect data for calendar year 1996; and the 1998 SPD CAPI instrument, used to collect data for calendar years 1997 through 2002.
SIPP Content. Information collected in the SIPP falls into two categories: core and topical module. 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 on a monthly basis, although a few core items are measured only as of the interview date (once every four months). Topical module questions, asked less frequently to produce in-depth information on specific subjects, ask about particular social and economic characteristics, as well as personal histories. Topics include assets and liabilities, school enrollment, marital history, fertility, migration, disability, and work history.
1997 SPD "Bridge" Content. From April through June of 1997, the 1997 SPD used a modified version of the March annual income supplement to the Current Population Survey (CPS), to collect information about the previous calendar year. The instrument consists of demographic questions (questions about age, race, sex, ethnic group, marital status, and other personal characteristics) and questions on a wide variety of income sources.
1998-2002 SPD Content. Data collection for the 1998-2002 SPD occurs once each year, in May through July, gathering information about the previous calendar year. The information collected includes economic, demographic, and social characteristics of the people interviewed. Questions about demographic and social characteristics include educational enrollment and work training, functional limitations and disability, and health care use and health insurance. Questions about economic characteristics include employment and earnings, income sources and amounts, assets, liabilities, program eligibility information, and food security. Information about children is also collected, including their school enrollment and enrichment activities, disability, health care, child care arrangements, contact with an absent parent, and payment of child support on their behalf. A separate, self-administered section of the CAPI questionnaire collects information from adults on marital relationship, marital conflict, and parental depression.
In 1998 and 2001, a separate, self-administered paper questionnaire collected information from adolescents — on family conflict, vocational goals, educational aspirations, crime-related violence, substance abuse, and sexual activity. In 2000, the SPD included a Children's Residential History Calendar (RHC), designed to collect complete childhood histories of all children in SPD respondents' households. The RHC measures the number and timing of moves that children make.
For 1999 and 2002, the SPD included additional questions on children's extended measures of well-being, positive behavior/social competence, and conflict between parents.Top
The SPD Data Products
The Census Bureau has designed a series of the SPD data products for public use: one interim calendar year file, for 1998 (to support preliminary analysis of income and program participation among the original cohort); six fully edited cross-sectional files, for 1997 through 2002; and three longitudinal files, containing fully edited, consistently-formatted, and longitudinally-processed core variables derived from the information collected over time. The three longitudinal files will contain data for the following years: (1) for 1992 - 1994 and 1996 - 1997; (2) for 1992 - 1994 and 1996 - 1999; and (3) for 1992 - 1994 and 1996 - 2001. Only the 1992 SIPP panel provided information for 1992.
The SIPP 1992 and 1993 Longitudinal files, the 1997 SPD Bridge file, the 1998 SPD file, and the SPD First Longitudinal file are available from Marketing Services Office, Customer Services Center, U. S. Census Bureau, Washington, D.C. 20233. An extract file of the SIPP 1992 and 1993 Longitudinal files are available for downloading from the SIPP Internet site at www.sipp.census.gov/sipp under "Data Access" using one of the following extraction systems: the FTP site: Federal Electronic Research and Review Extraction Tool or using the DataFerrett Application which can be downloaded and installed at dataferrett.census.gov. Extract files of the 1997 SPD Bridge file are available for downloading from the SPD Internet site at www.spd.census.gov/spd under Data Access using DataFerrett. Files are also available on CD-ROM (compact disc-readable) in ASCII format (call 301-763-4636 for price information).Top
Comparison to Other Surveys
The Census Bureau's Survey of Income and Program Participation (SIPP) and the University of Michigan's Panel Study of Income Dynamics (PSID) are two longitudinal surveys that can also be used to study the effect of welfare reform. Analysts can use the SIPP data to address many of the same questions they can address with the SPD data–except for the differences experienced by families and individuals, before and after national welfare reform. Because the PSID has interviewed individuals from the families in its core sample every year since 1968, the PSID data can be used to measure differences experienced by families and individuals, before and after national welfare reform. Additional information on the SIPP is available on the Internet at this address: www.sipp.census.gov/sipp. Additional information on the PSID is available on the Internet at this address: psidonline.isr.umich.edu.
The Census Bureau's Current Population Survey (CPS) and the Urban Institute's National Survey of American Families (NSAF) are two cross-sectional surveys that can also be used to study the effect of welfare reform. The CPS has already been used to study other non-experimental welfare changes, such as those made in 1981 to the Aid to Families with Dependent Children (AFDC) program. The NSAF data are being collected specifically to evaluate the 1996 changes. Additional information on the CPS is available on the Internet at this address: www.bls.census.gov/cps. Additional information on the NSAF is available on the Internet at this address: www.urban.org/Content/Research/NewFederalism/NSAF/Overview.
Researchers may also examine the effects of welfare reform by looking at pre-existing continuing experimental studies, such as welfare waiver demonstration projects. Other useful approaches include ethnographic studies, such as the Manpower Demonstration Research Corporations' Urban Change Study and the General Accounting Office's (GAO's) studies of welfare reform in selected states. Each of these surveys and studies will provide insights into some aspects of welfare reform and should be considered part of the portfolio needed to understand that major program change. Additional information on the Urban Change Study is available on the Internet at this address: www.mdrc.org/welfare_reform.htm. Additional information on the GAO's studies of welfare reform is available on the Internet by going to the GAO website at www.gao.gov and then searching for the phrase "welfare reform."
The SPD is a unique tool for evaluating reform because of its welfare reform-specific content, and because it offers the ability to analyze the economic and social well-being of families at two points in time as well as longitudinally over a 10-year period.