Tuesday, March 22, 2011

Question #4: When to Use ACS data

4. If the same data appear in the 2010 Decennial Census and in the ACS, which should I use?
A. It depends. The decennial census is the most accurate source of data for counts of population and housing because it is based on a full enumeration. And, if the data you want are available from the 2010 Decennial Census, they should be used. However, as time goes on, the 2010 Decennial Census data will quickly become out-of-date in many places, and the ACS may become the better choice. Click to see other Frequently Asked Questions

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  1. Is it still preferable to use ACS data over current year estimates?

  2. For lots of data that used to appear on the census long form, the only option is ACS data, but you'll want to see whether your unit of analysis is small enough to use 1 year estimates rather than 3 year or 5 year estimates. For many localities, only the 5 year sample is granular enough to give significant results.
    For data that is available through the census, the comprehensiveness of the count makes the census more useful than the ACS.


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