By James Clary
On Thursday, September 22nd, the U.S. Census Bureau released the 2010 one-year estimates for the American Community Survey (ACS). The ACS replaced the Census long form, and uses monthly surveys to track a variety of economic, demographic, and social characteristics around the country.
The ACS produces one-year, three-year, and five-year estimates to provide statistical information on geographic areas containing different population levels. It is important to note that these are estimates that are created from several months of observation (rather than being an estimate at a particular point in time as the decennial census or the monthly unemployment numbers). This approach, along with the uncertainty caused by small sample sizes, indicates a need for caution when evaluating short-term trends. One example comes from the median age in Hampton Roads which increased from 34.7 in 2009 to 35.7 in 2010; however, this data has a margin of error 0.2 years, meaning that the median age could have increased by as much as 1.4 years, or as little as 0.6 years.
The primary use of the ACS annual data is as a snapshot to place the region in context with other regions around the nation, and to better perceive the local strengths and weaknesses.