The Leadership Conference on Civil and Human Rights

In this report:

Table of Contents

1. Overview
2. The Importance of the Census
3. Census Accuracy: The Undercount (and Overcount)
4. Census 2010: Key Operations and Milestones; How You Can Get Involved
   1. Overview of the census plan
   2. What you need to know
   3. How you can help
5. Additional Information
   1. Frequently asked questions
   2. Facts and figures
   3. Census history

Determining the Undercount/Overcount

The Census Bureau began developing methods to better measure census accuracy when, in 1940, the census grossly underestimated the number of men that would enlist for the draft because of the miscount of young black men. Using information from birth and death records, past censuses, and information on immigration, the Bureau developed a system of measuring the undercount called Demographic Analysis. This method has been used as an independent check on census accuracy at the national level since 1940; however, it can only give national undercount numbers.

The 2000 census included a procedure, called the Accuracy and Coverage Evaluation survey, to check for missing housing units and people who were not reported on a census form. However, concerns about the reliability of the accuracy evaluation led the Census Bureau to revise its estimates of undercounts and overcounts several times and ultimately to conclude that it could not use the estimates to make any corrections to the original census numbers.

In 2003, the Census Bureau announced that the 2010 census would not include the possibility of a statistical adjustment based on a coverage measurement survey, citing concerns about the methodology’s reliability and the Bureau’s ability to produce adjusted population figures in time to meet legal deadlines for apportionment and redistricting. The 2010 census will include a quality check survey of 300,000 addresses (called the Census Coverage Measurement survey), to estimate undercounts and overcounts for the nation as a whole and for states. The Census Bureau plans to publish the estimates, which will measure coverage by race and Hispanic origin, gender, age, and renter/owner status at the national level only, in 2012. It will not use that analysis to “adjust” the original population figures, however.

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