National Academy of Sciences

National Academy of Engineering

Institute of Medicine

National Research Council

Panel to Review the 2000 Census

Committee on National Statistics

Division of Behavioral and Social Sciences and Education

November 26, 2001

Mr. William Barron

Acting Director

U.S. Census Bureau
Washington, D.C. 20233

Dear Mr. Barron:

This letter from the Panel to Review the 2000 Census comments on the Census Bureau’s October 17, 2001, decision that unadjusted data from the 2000 census enumeration process should be used for the allocation of federal funds and other purposes. This decision follows an earlier decision by the Bureau on March 1, 2001, that unadjusted census counts should be used for redrawing congressional district boundaries. The Bureau released extensive evaluation materials to accompany both decisions.1

In our interim report (see Part II), we concluded that the 2000 census was well executed in many respects although—like every census—there were some problems. The latest set of Census Bureau evaluations make it clear that there were considerably more errors of overcounting in the census than were originally estimated by the Accuracy and Coverage Evaluation (A.C.E.) Program.2 These evaluations—while not yet complete—suggest that because the A.C.E. did not identify a substantial number of these overcounting errors (mostly duplicates), the use of the original A.C.E. data to adjust the census could lead to overstating the population. Accordingly, the panel concludes that the Census Bureau’s decision not to adjust the census at this time is justifiable. However, the panel urges the Bureau to complete the research necessary to develop reliable revised estimates of the net coverage errors in the census, particularly for population groups, in order to determine whether their use would improve the Bureau’s population estimates that are regularly produced during the postcensal period.


The Bureau’s evaluations are available at


The A.C.E. was designed to provide the basis for an adjustment of the census for net population undercount through dual-systems estimation. Our panel is charged to review the statistical methods of the 2000 census, particularly the use of the A.C.E. and dual-systems estimation, and other census procedures that may affect the completeness and quality of the data.

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement