Assessing the accuracy of the census is essential given that census data are used to apportion seats in Congress, to redraw congressional districts, and for many other public and private purposes. The U.S. Census Bureau's (Bureau) Census Coverage Measurement program (CCM) is to assess the accuracy of the 2010 Census and improve the design of operations for the 2020 Census. In April 2008, GAO recommended that the Bureau identify how it would relate CCM results--where the 2010 Census was accurate and inaccurate--to census operations to improve future censuses. Knowing where the 2010 Census was inaccurate can help inform research to improve the 2020 Census. GAO was asked to examine (1) the status of CCM planning and (2) the effects of design decisions since GAO issued its April 2008 report. GAO reviewed Bureau documents related to CCM design and National Academy of Sciences reports, and interviewed responsible Bureau officials.
Recommendations for Executive Action
|Department of Commerce||1. To improve the usefulness of CCM for 2020, and to help the Bureau achieve its goal of using CCM to improve the 2020 Census, the Secretary of Commerce should require the Director of the U.S. Census Bureau to better document links between the 2010 CCM program and 2020 Census planning, integrating the goal of using the CCM program to improve Census 2020, such as with CCM results and data, into those broader plans for 2020.|
|Department of Commerce||2. To improve the usefulness of CCM for 2020, and to ensure that Bureau datasets from the 2010 Census can be used with other Bureau datasets to support research that could improve the census and CCM, the Secretary of Commerce should require the Director of the U.S. Census Bureau to complete the Master Trace Project's assessment of how key census and CCM data systems are, or can be, linked to each other; identify any potential data gaps; and identify other related steps for future action.|
|Department of Commerce||3. To improve the usefulness of CCM for 2020, and to help the Bureau better determine the optimal timing of future coverage measurement data collection, the Secretary of Commerce should require the Director of the U.S. Census Bureau to fully assess the trade-offs between starting the data collection earlier, with the possibility of introducing contamination errors, and starting later, with the possibility of introducing recall errors.|