The SPD Bridge file was processed using programs for the March Current Population Survey Demographic Supplement. These data have undergone limited editing and review and should be used carefully.
Interim Calendar Year Files
So that the research community can assess the quality of the SPD sample and make some preliminary assessment of the immediate impact of welfare reform, we are issuing this interim file from the 1997 bridge survey. The interim file is identical to the March CPS in format. It repeats the March CPS content and includes additional information from the SPD. This additional information includes panel weights corresponding to the cohort and the following match keys needed to merge SPD and earlier SIPP data:
SIPP Panel Number SIPP_PNL
Sample Unit Identification Number PP_ID
Entry Address ID PP_ENTRY
Person Number PP_PNUM
A note of caution about this interim file. It will appear to be a cross-section snapshot of the population, like the March CPS. It is important to emphasize that it is not because there has been differential nonresponse over the life of the SIPP and SPD Bridge surveys. Weighting compensates for some of the bias, but may not totally eliminate its effect on estimates. It is simply one segment in the array of longitudinal data being produced for SPD. The weights are longitudinal and only valid to estimate 1996 characteristics of the 1992/1993 SIPP cohorts. Children born since the beginning of the SIPP panel do not receive longitudinal weights in this first file so the distribution of population by age will be skewed toward the older population. However, users can construct an approximate weight for these children by assigning the weights of the mother to each child.
There are several relationship variables on the person record. Only the A_EXPRRP variable has been reviewed and edited. A_EXPRRP is the "edited relationship to reference person." We recommend using A_EXPRRP in your analysis and not using, or using with caution, the following relationship variables:A_FAMREL, A_PFREL, HHDREL, FAMREL, and HHDFMX. These variables will be edited for the forthcoming SPD longitudinal file.