2010 Census:

Plans for Census Coverage Measurement Are on Track, but Additional Steps Will Improve Its Usefulness

GAO-10-324: Published: Apr 23, 2010. Publicly Released: Apr 23, 2010.

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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.

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.

Recommendations for Executive Action

  1. Status: Closed - Implemented

    Comments: In June 2011, the Bureau released is business plan for the 2020 Census, including detailed descriptions of its research projects, including reference to use of the 2010 Census Coverage Measurement(CCM) results. This integration of the 2010 CCM results into 2020 planning will help ensure that the Bureau does not miss opportunity to design or target 2020 Census operations to improve their effectiveness or reduce cost.

    Recommendation: 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.

    Agency Affected: Department of Commerce

  2. Status: Closed - Implemented

    Comments: In June 2011, the Bureau created a data warehouse to be used for research throughout the coming decade for all 2010 decennial data resulting from the Master Trace Project, following a broad data call to identify gaps. In February 2013, the Bureau further formalized the data warehousing with an internal memorandum of understanding that laid out the process by which researchers could obtain data across data sets. This commitment to ensuring that the Bureau's far-reaching datasets are accessible for operations research will help support Bureau efforts to improve the effectiveness of future census operations.

    Recommendation: 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.

    Agency Affected: Department of Commerce

  3. Status: Closed - Implemented

    Comments: In June 2011, the Bureau released its business plan for the 2020 Census, including detailed descriptions of its research projects, including descriptions of research designed to answer the question of what is the optimal timing for CCM data collection. This assessment will help ensure that the Bureau's decisions for the timing of CCM in 2020 will be well-justified and will minimize the risk of errors entering it measures of census quality.

    Recommendation: 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.

    Agency Affected: Department of Commerce

 

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