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Friday, June 8, 2001

New Report Questions Statistical Adjustment

WASHINGTON – A new report issued today by the Congressional Members of the U.S. Census Monitoring Board examines the scientific methodology behind statistical adjustment.

“The 2000 census was the most accurate census in history,” said board Co-Chair A. Mark Neuman.  “With the dramatic reduction in the differential undercount compared to 1990, one can see why the professionals at the Census Bureau chose not to recommend the use of statistically adjusted numbers.  In the coming weeks and months we will be studying to what extent statistical adjustment would have put persons missed in the census back into the neighborhoods where they were missed,” he said.  “We must not only attempt to count everyone living in America, we must make sure they are counted at the correct address.”

“There are other considerations we feel everyone should understand about the statistical adjustment methodology,” Neuman continued.  Among these are the roles of “post-strata” and “adjustment factors” in adjustment, and how data from just 800 people in one type of area (e.g. large metropolitan areas) could have been used to adjust data for millions of people nationwide.

Board member Dr. David Murray also commented on the assumptions behind statistical adjustment.  “Adjusting the count of certain areas with data for persons from radically different areas is scientifically problematic, and that is what adjustment would do,” he said.  “Adjusting data for persons from New York City with data from persons in Miami and Seattle has troubling implications, especially when there are important geographic dimensions in the use of census data.”

Other geographic examples are highlighted in the report, including that of the Gila River Reservation in Arizona, whose data would be adjusted with data from other Native American tribes, such as the Oneida Nation in New York.

The U.S. Census Monitoring Board is a bipartisan panel created by Congress to oversee all aspects of the 2000 Census.  This report was produced by the congressionally appointed members.  Information regarding the Census Monitoring Board and the 2000 census can be found on our web page at

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