data from the census and replacing it with other alternatives until data from these alternatives are available, used and tested, and preferred as a replacement to the census. A variety of census data users have informed the panel that they primarily rely and wish to rely on the census for small-area data. Small-area data users have, however, indicated the value of more timely small-area estimates from the Census Bureau, the value of a mid-decade census or a large mid-decade sample survey, and the value of being able to provide geographically referenced estimates from administrative records. These alternatives deserve further study. None of the alternatives, however, are feasible replacements for the census at this time.
We turn to an examination of several case studies on improving intercensal small-area data. The first case study discusses methods used by the Department of Defense for estimating the number of persons qualified for military service. The second study discusses the procedures used by the Bureau of Labor Statistics to provide monthly employment and unemployment estimates for states, the District of Columbia, and 2,600 labor-market areas. The third case study describes Census Bureau work to prepare annual estimates of income and poverty. The last case study examines possible ways to improve subnational estimates for the migrant and seasonal farmworker population.
A recent workshop convened by the Committee on National Statistics, at the request of the Department of Defense, assessed alternative techniques to develop small-area estimates of those qualified for military service (Committee on National Statistics, 1989). The ultimate aim of the workshop was to decide what method would provide the ''best" estimates of the qualified military persons available in small areas (usually counties) on an annual basis for the country. Such estimates would offer a common basis for comparative recruiting goals, at small areas, within the armed services.
For military recruitment into the enlisted ranks, the key concept for data estimates is the qualified military available (QMA), defined as the number of male high school graduates, ages 17-21 years, who mentally and physically qualify and are of suitable moral character. The QMA is the current target population by the armed services for new military recruits. Women are excluded from the current QMA because the services are oversubscribed in their recruitment of women.
Preparing small-area estimates for the QMA may be thought of as a successive narrowing of the target population. The step-down approach at estimating the QMA, at any geographic level, starts with the base population and successively restricts the nonqualifying groups. The remaining group is the QMA. The approach for county estimates for the QMA is as follows:1