The American Community Survey (ACS) is a nationwide survey conducted on an ongoing basis to collect data about the nation, states, counties, and places. The data are released in single-year, 5-year, and 3-year time periods.
The ACS estimates replaces information formerly gathered in the decennial census; data on the "Short form"/sample.
ACS estimates are time periods not a point in time.
Do: express data in time periods
“The child poverty rate for the 2005-2007 period was X percent.”
Do: compare data using same types of estimates
Do: compare estimates using data from the same survey years (periods)
Do: compare data from non-overlapping periods
Example: 2005-2007 ACS 3-year estimate and the 2008-2010 ACS 3-year estimate
Don't: refer to data as a year (use the time period)
Don't: compare estimates from overlapping periods
Example: don't compare 2005-2007 ACS 3-year estimates and 2006-2008 ACS 3-year estimates