The Bureau is not planning to use CCM to adjust the 2010 Census. The Bureau Has Finalized Decisions in Some Key Areas Since Our 2008 Report

Since our April 2008 report, the Bureau has finalized its plans in key areas  of the CCM program including CCM’s goals, the timing of operations, and  the timing and types of results to be produced. Planning continues in other  areas, such as developing estimation methods, evaluating the CCM  program, and implementing its Master Trace Project. In addition, while the deadlines for finalizing  CCM estimation methods have not yet passed, the Bureau has many of its  default plans already in place. Table 1  shows the status of the Bureau’s plans for the design of CCM in each of  these areas. Still, in some cases, it will be  important for the Bureau to take additional actions to help ensure the  results of CCM are as useful as they could be to inform Bureau decisions  on improving future censuses and coverage measurement efforts. These early planning efforts are described in a series of decision  memorandums issued in the summer of 2009, and include milestones  leading up to a census test in April 2014, descriptions of planning phases,  and a list of the various organizational components that conduct the  census. Importantly, by creating a  “roadmap” that describes, for example, what the Bureau might learn from  CCM or how the results might feed into early 2020 Census planning, the  Bureau will better ensure that there are no gaps or overlaps in the use of  CCM in early 2020 planning. The Master Trace Project is  intended to ensure that these datasets and systems can be used together,  or linked, to support detailed research into the causes of census coverage  problems and facilitate research on the possible interactions of future  operations. In particular, the Bureau has not yet  completed an inventory of the census databases that might be of potential  interest for future research, identified which archived versions might be  most useful, or mapped out how they might be archived and linked. Doing this quickly will also be  important as Census 2010 is underway and it could become increasingly  difficult to make changes to database structures or archival and data  storage plans if the Bureau’s assessments determine that changes are  necessary. In June 2009,  the Bureau decided to keep the originally scheduled start on August 14,  2010. Furthermore, parts of this census operation are new in 2010, and end later  than similar operations did in 2000. Moving forward, additional research on the trade-offs between recall bias  and contamination errors could help the Bureau more fully understand the  implications of choosing various start times for PI on the resulting  estimates of coverage error and better determine the optimal timing of PI  in future censuses. Conclusions

Assessing the accuracy of the census is an essential step in improving  current and future censuses. Recommendations for Executive Action

We recommend that the Secretary of Commerce require the Director of  the U.S. Census Bureau to take the following three actions to improve the  usefulness of CCM for 2020:  To help the Bureau achieve its goal of using CCM to improve the 2020  Census, 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.
Why GAO Did This Study

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.

What GAO Found

Since GAO's April 2008 report, the Bureau has finalized plans for 2010 CCM goals, the timing of operations, and the types of results to be produced. Planning continues in other areas, such as developing estimation methods, evaluating the CCM program, and implementing its Master Trace Project, which would enable the Bureau to link its datasets and systems to support a broad range of research. The deadlines for some of these plans have not yet passed, but the Bureau already has default plans in place in case further changes do not occur. In mid-December, the Director decided to make some additional changes to the CCM program to improve the quality of CCM results. GAO found that additional actions on Bureau decisions may make CCM more useful in informing Bureau decisions on future census and coverage measurement efforts: (1) The Bureau's 2020 planning efforts are described in a series of decision memoranda issued in the summer of 2009. However, the Bureau has not yet taken steps to integrate CCM results with early 2020 planning to prepare for a census test in 2014. By describing, for example, what the Bureau might learn from CCM or how the results might feed into 2020 Census planning, the Bureau will better ensure that there are no gaps or overlaps in the use of CCM for early 2020 planning. (2) In September 2009, the Bureau began its Master Trace Project, which is intended to ensure that its datasets and systems can be used together to support detailed research into the causes of census coverage problems and facilitate research on the possible interactions of future operations. At the time of this review, the Bureau had not yet completed an inventory of the census databases that might be of potential interest for future research, identified which archived versions might be most useful, or mapped out how they might be archived and linked. Doing this quickly will be important as the census is already underway and it will be difficult to make changes to database structures or archival and data storage plans if the Bureau's assessments determine that changes are necessary. (3) The Bureau reviewed its previous decision to start CCM's Person Interviewing operation later than it did in 2000, and decided in June 2009 not to change it. However, the Bureau does not have a plan to assess the trade-offs in error between earlier and later start dates. Additional research on the trade-offs of different start dates could help the Bureau more fully understand the implications of CCM timing decisions on the resulting estimates of coverage error and better determine the optimal timing of Person Interviewing in future censuses.