Sample supplementation involves planning the sample design, carrying out household screenings, and data collection. It will require substantial efforts and costs and obviously should be used only as a last resource, that is when combining years is inadequate. We will use the results from Section 4 to identify surveys needing supplementation. However, we emphasize that such decisions cannot be fully made without careful consideration of the precision needed for specific policy purposes, which is beyond the scope of this report. Consequently, the surveys below and the subgroups for which supplementation is required should be thought of as suggestive rather than as actual recommendations.
We will mostly use the information in Section 4 of this report to identify surveys requiring supplementation. For periodic, rather than annual surveys, Section 3 describes the ability of each survey to provide useful data on minority subgroups.
Supplementation obviously is not required for the National Vital Statistics data sets, Census 2000, and the ACS. Averaging over time in CPS and NHIS, up to 5 years, would provide reasonable statistics for most of the minority subgroups. However, the samples for a few of the smaller subgroups (e.g., Cubans and Hawaiians) would still be quite small, and if those populations are of particular interest, then supplementation is needed. The NHIS Hispanic sample is even larger than CPS so that with the exception of Cuban-Americans, multi-year averages would provide data for adequate precision. The NHIS samples of American Indians or Alaska Natives and APIs are about the same as CPS and multi-year averages will be sufficient for most analytic purposes.
Five-year averages in NIS, NHSDA, and MEPS are sufficient for all Hispanic subgroups, with the possible exception of Cubans, but even 5 years will satisfy only minimal standards for the API subgroups. The American Indian or Alaska Natives sample will permit moderately detailed analysis in NIS but not in NHSDA or MEPS.
The surveys requiring supplementation for all, or almost all, minority subgroups are: NSFG, NHANES, MCBS, NHES, ECLS-B, and ECLS-K.