What topic(s) am I looking for?
The ACS and the Census provide population counts, but not all topics appear in both. To compare, check out the Census Bureau's A-Z Subject Index or look at the questions that were asked: Census and ACS.
How recent does it need to be?
ACS is the most recent data, with ACS 1-year estimates being the most recent of the ACS releases.
How accurate does it need to be?
Census data is the most accurate; ACS 5-year estimates are the most accurate of the ACS releases.
Which geographies should I study?
ACS 1-year and 3-year estimates only exist for larger geographies; for smaller geographies you'll need to use ACS 5-year estimates or Census data. For NYC geographies, you'll need to use a special source like InfoShare Online and your choice of datasets will be more limited.
Data set |
Time Period | Sample | Coverage |
Census 2010 | April 1, 2010 | All Americans living in households | All US Census geographies |
ACS 1-year estimates* | 12 months of collected data | Representative sample; approximately 3 million households sampled per year | US Census geographies with populations larger than 65,000 |
ACS 3-year estimates* | 36 months of collected data | Representative sample; approximately 3 million households sampled per year | US Census geographies with populations larger than 20,000 |
ACS 5-year estimates* | 60 months of collected data | Representative sample; approximately 3 million households sampled per year | All US Census geographies |
*For more on choosing which ACS estimates to use, see "When to use 1-year, 3-year, or 5-year estimates" from the Census Bureau.