a 1999 Supreme Court decision precluded the use of alternative counts, when based on sampling, for use in reapportionment. In addition, it is difficult to provide alternative counts in time for reapportioning congressional districts. Consequently, for the 2010 census coverage measurement program, the Census Bureau has stated its intent to deemphasize the goal of providing alternative counts and is instead planning on focusing its coverage measurement program on the second goal of improving census processes.
The panel strongly supports the Census Bureau’s change in goal. However, the panel finds that the current plans for data collection, data analysis, and data products are still too oriented toward measurement of net coverage error to fully exploit this new focus. Although the Census Bureau has taken several important steps to revise data collection and analysis procedures and data products, the panel recommends further steps to enhance the value of coverage measurement for the improvement of future census processes.
Recommendation 1: The Census Bureau should more completely shift its focus in coverage measurement from that of collecting data and developing statistical models with the goal of estimating net coverage error to that of collecting data and developing statistical models that support the improvement of census processes.
To help achieve this new goal, instead of only measuring net census error, the Census Bureau also plans to measure the four components of census coverage error: (1) census omissions, (2) census duplications, (3) erroneous census enumerations, and (4) census enumerations in the wrong location. The panel supports these plans, since different types of coverage errors are caused by different interactions between census processes and housing units and their occupants. The estimation of these four components of coverage error can be supported by the general structure of the data collection and matching that is carried out in support of dual-systems estimation, though modified and expanded to support this different purpose. The panel finds, however, that the Bureau’s plans could be more fully developed for this purpose.
Recommendation 9: The Census Bureau should further develop and refine its framework for defining the four basic types of census coverage error and measuring their frequency of occurrence. The Census Bureau should also develop plans for operationalizing the measurement of these components using data from the census and the census coverage measurement program.