contribute to new and improved measurement over the longer term. The continuous design of the ACS, which may initially challenge users to adapt their long-form-sample-based applications to the new data, provides the platform for developing important innovative applications for the future.

There are at least five ways in which the ACS could contribute to new and improved measurement. They involve (1) more timely and accurate measures of key indicators for small geographic areas by combining information from the ACS, other surveys, and administrative records; (2) measures of seasonal population fluctuations and multiple residences; (3) cost-effective, up-to-date data collection for rare populations; (4) improved population estimates; and (5) improved estimates from other household surveys (other surveys may also help improve the ACS).

7-D.1
Small-Area Estimates

The planned ACS estimates for geographic areas involve accumulating and averaging 12, 36, and 60 months of data, depending on population size. For small counties, cities, and other areas for which 3-year or 5-year period estimates are provided, many users would very likely prefer continuously updated 1-year estimates for the latest year rather than estimates that represent an average over a longer period of time.

Modern small-area estimation methods that borrow information across time, geography, and data sources could be used to develop indirect 1-year period estimates for key indicators, such as poverty, unemployment, food stamp participation, and others, for all counties and cities (not just those with fewer than 65,000 people). Statistical models could use data from the ACS and relevant administrative records to generate indirect estimates that would likely improve on the direct ACS estimates in precision, accuracy, and currency. Depending on the availability of administrative records, the indirect estimates might lag the latest release of the period estimates, although models could possibly be developed to project the indirect estimates forward 1 or 2 years to represent the latest year.

Small-area estimation models that use the ACS could also incorporate estimates from other surveys when those surveys are believed to provide estimates of higher quality than the ACS estimates. For example, the Current Population Survey (CPS) very likely provides more accurate measures of labor force, employment, and unemployment status than the ACS (see Section 2-B.2.e). The CPS includes a more detailed set of questions and has other design features, such as a fixed reference week for measurement, to reduce nonsampling error.4 Although the CPS sample size, even when accumulated for 12 months, does not support precise estimates for subnational



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