Extending the Utility of Federal Data Bases. Content of Report


This Task 3 report has two objectives:

  1. To examine the ability of the selected statistical databases to provide data on detailed Asian and Hispanic subgroups and on American Indians and Alaska Natives with adequate precision for most practical uses; and
  2. To suggest and evaluate methods that could be used to enhance this ability for surveys with insufficient sample size for the provision of reasonably reliable statistics on these minorities.

The report begins with a brief summary of the Task 2 findings; Task 2 inventoried the major characteristics of the surveys and other databases covered in this report which relate to their ability to provide data for the subpopulations. It continues in Section 2 with a discussion of the methodological and statistical issues that need to be taken into account in determining the applicable standards for accuracy, and possible courses of action to achieve this action when current samples are too small to provide estimates with the desired reliability.

Section 3 indicates which surveys meet standards of reliability for at least some of the race/ethnic subgroups. To assist ASPE in determining the conditions for which the data would be useful, we have used several alternate levels of reliability. (In Section 2.1, we suggest some guidelines for choosing what could be considered adequate precision for specific kinds of analyses.) Most of the discussion of adequacy or inadequacy of the data refers to the size of the sampling errors. The sampling errors in a survey depend on both the sample size and the surveys design effects; average design effects are reported in Section 3.3. However, we also point out surveys for which only some of the subgroups are identified on the data file, and consequently, complete analyses of all subgroups are not possible. Idiosyncratic features of some of the surveys that complicate the discussion also are noted.

Sections 4, 5, and 6 describe methods of overcoming the small sample sizes for the detailed race/ethnic groups in most of the surveys. Sections 4 and 5 cover relatively inexpensive methods; combining several years of data for surveys conducted annually in Section 4, and combining results of different surveys for items collected in common, in Section 5. When these two procedures for enhancing the quality are not sufficient, sample supplementation is required. Section 6 provides information on the sample designs that are efficient for minority supplementation and other statistical procedures that could be used.

Section 7 briefly summarizes the material in this report.