Although these surveys all include content relevant to welfare reform evaluations, most are conducted for purposes other than welfare population monitoring and evaluation. Only the Survey of Program Dynamics has as its primary purpose the evaluation of welfare reform, although the SIPP, which was established before PRWORA, also has a special role as it was created to measure government and welfare program participation.

Population Coverage

National-level surveys are designed to produce analyses that are representative of the national population and, hence, are useful for producing estimates of the well-being of the nation as a whole.1 Most of these surveys are not, however, representative of smaller geographic areas, which is a significant disadvantage for studying welfare reform in an era of devolution. Data from the census long form are representative of state and local areas, but they are only produced once every 10 years, and so are not appropriate for timely monitoring or evaluation purposes. The ACS will be representative of smaller areas on an annual basis, and, hence, will be a major improvement in providing state and local level data on a far more timely basis. The ACS will be representative of states, large counties and governmental units with populations over 65,000. Eventually, multiyear averaged data representative of smaller areas will also be produced. Other national-level data sets (SIPP, SPD, NLSY, PSID) are of limited use for state-level monitoring because the state sample sizes are too small for precise estimates of state-level measures. The March CPS is large enough to produce annual state-level estimates, but the precision of estimates in most states is low.2 Other national surveys are representative of some states. For example, the Urban Institute’s NSAF is designed to be representative in 13 states (Alabama, California, Colorado, Florida, Massachusetts, Michigan, Minnesota, Mississippi, New Jersey, New York, Texas, Washington, and Wisconsin), though sample sizes for the low-income welfare participant population per se are quite modest. The SIPP and SPD are not representative of all states, but sample sizes are large enough in some states that state level estimates of outcomes can be produced with reasonable precision.


Except for the census long form, these surveys exclude institutionalized persons, much of the military, and the homeless populations, although the NLSY and PSID studies do follow sample members in and out of institutions. The NLSY79 is representative only of those aged 14–22 in 1979; the NLSY97 is nationally representative of youths aged 12–16 in 1997. The NSAF is representative of the nonelderly population.


The Census Bureau has funding to improve the precision of state-level estimates of the number of children with health insurance coverage by family income, age, race and ethnicity. Initial plans call for a significant increase in the sample size of the March Supplement, which should enhance the use of the CPS for state-level monitoring and evaluation.

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