1990 Post-Census Local Review revealed inaccurate counts in need of review.
A final quality check of Bureau data, which usually contain a number of discrepancies, is necessary.
An accurate count is more difficult in areas of high growth.
Municipalities are dependent on the accuracy of the count for federal (and often state) revenue.
 

"During the 1990 post-census review, the City of Fairfield identified 1,135 dwelling units (approximately 3,400 people) that had not been counted in the census. This undercount was eventually corrected by the Census Bureau. If the City had not had the opportunity to correct this undercount, the City would have experienced revenue losses of up to $211,500 per year from the State of California and a potential loss in Community Development Block Grant Funds of $30,300 per year."

George Pettygrove, Mayor, Fairfield, California

"In 1990, Elk Grove Village reviewed the Census Bureau’s preliminary count. Village staff found that a newly constructed subdivision had failed to be counted which included 349 residents. Furthermore, based on the per capita revenue dispensed by the State of Illinois, Elk Grove Village would have lost over $35,000 in annual revenue (almost $250,000 in total) had the review process not existed."

Craig B. Johnson, Elk Grove Village President.

"Based on our experience and the national information provided in your letter, we feel our first comment must be to urge the Secretary of Commerce to reconsider a very ill-advised decision. Census 2000 is of too great a significance to cities to allow the data to be used without our first having an opportunity to review it."

Kirk Humphreys, Mayor, City of Oklahoma City