Two Sets of County Population Estimates: How and Why Do they Differ?

Signe I. Wetrogan, Independent Consultant

The Population Estimates Program of the U.S. Census Bureau is evaluating different methods to produce the official estimates. This research will examine two sets of population estimates for states and counties developed for the post-2000 period; one set developed using the current administrative records method and an alternative set developed using a housing unit approach. Since each method has its unique set of weaknesses and biases, large difference in results often occur. The research will draw upon earlier research that examined the accuracy and differences in two sets of county population estimates prepared for 2000. The current research will examine the differences in the results for the post-2000 period. The difference in estimate results for the post-2000 period will be compared to differences observed in prior research. The research will also explore county typologies that may be related to the differences in estimate results.