The American Community Survey: Warmer (More Current), but Fuzzier (Less Precise) than the Decennial Census

The American Community Survey, which will replace data many planners rely on from the decennial Census long form, is finally in progress. The first nationwide data for places of 65,000 or more was released in the summer of 2006. It has several interesting implications for planning. On the one hand, more current data will eliminate many of the inaccuracies introduced by projection-based updates of stale census data. On the other, smaller sample sizes will mean we will have less precise estimates. Because the ACS will use averaged rather than point-in-time data, it will measure slightly different things than the decennial census. Finally, planners should be alert to the opportunities they will have to improve local data quality by improving the address file from which the sample is drawn.