The 1990 and 2000 Census Adjustment Plans

A revised plan for the 2000 Decennial Census was announced in a 24 February 1999 Bureau of the Census publication and a press statement by K. Prewitt, Director of the Bureau of the Census. Census 2000 will include counts and "adjusted" counts. The adjustments involve complicated procedures and calculations on data from a sample of blocks, extrapolated throughout the country to demographic groups called "post-strata." The 2000 adjustment plan is called Accuracy and Coverage Evaluation (ACE). ACE is quite similar to the 1990 adjustment plan, called the Post-Enumeration Survey (PES). The 1990 PES fails some plausibility checks and mightwell havehave reduced the accuracy of counts and state shares. ACE and PES differ in sample size, data capture, timing, record matching, poststratification, methods to compensate for missing data, the treatment of movers, and details of the data analysis. ACE improves on PES in a number of ways, including using a larger sample, using a simpler model to..