whenever resources become available are methods to impute missing data responses and methods to include the variability from item imputation in addition to sampling error in estimating the standard errors of ACS estimates. Item nonresponse is less of a problem than it was in the 2000 long-form sample, but the effects of the imputation procedures should still be investigated. The Census Bureau should also investigate the utility of using more sophisticated imputation methods than those currently being employed. It should evaluate alternative methods for including the variability from item imputation in the estimates of the sampling errors for estimates from the ACS (see Bell  for research on including imputation in variances for estimates from the 2000 census).
Finally, it will be important for the Census Bureau to have a process for periodically reviewing its research and evaluation priorities and adjusting them as appropriate. It may be that an area thought to be of pressing concern appears less so upon initial investigation, whereas an area that was not high priority to begin with becomes of increasing concern for uses of the data. Close consultation with users and monitoring of ACS data quality will help the Census Bureau keep its research and evaluation program on track.
The Census Bureau will also need to periodically reevaluate its research priorities in light of available funding and staff. The Census Bureau should plan its research and evaluation program from the beginning to involve both intramural projects by its own staff and extramural work by outside researchers. In this way, it can better ensure that there are always highly qualified researchers actively assessing the ACS even if in-house staff are pulled away on production and other priorities.
Recommendation 7-9: The Census Bureau should assign priority to the following topics for research and development: sample size and allocation; the MAF; population controls; residence rules; estimates of change with multiyear averages; comparisons with other surveys and administrative records; and the development of automated tools for data quality review of ACS products.
At the present time, the ACS is viewed by the Census Bureau and data users primarily as a replacement for the long-form sample. While the panel agrees with that thrust in the short term, neither the Census Bureau nor the user community should lose sight of the vast potential for the ACS to