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American Community Survey

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Comparing ACS Data

The strength of the American Community Survey is in estimating characteristic distributions. We recommend users compare derived measures such as percents, means, medians, and rates rather than estimates of population totals. If you are looking for population totals, we recommend the 2010 Census or Population Estimates Program.

Use numbers from the 2010 Census to obtain counts of the population and their basic characteristics (sex, age, race, Hispanic origin, and homeowner status).

Use data from the Census Bureau's Population Estimates Program in the years between censuses. The Census Bureau's Population Estimates Program produces official population estimates for the nation, states, counties, cities and towns, plus housing unit estimates for states and counties.

It is also important to keep in mind that all American Community Survey data are estimates. We collect data from a sample of the population in the United States and Puerto Rico rather than from the whole population. To help you interpret the reliability of the estimates, the Census Bureau publishes a margin of error (MOE) for every ACS estimate.

Can I compare...?

American Community Survey 1-Year estimates with other data ?

CheckedACS 1-year estimates with Census 2000

CheckedACS 1-year estimates from different years.

CheckedUse Caution: Because ACS variables change over time, some areas and subjects must be compared with caution, or not compared at all.

Use the left navigation to get yearly guidance on specific topics/subjects.

ACS estimates with Census 2000?

CheckedACS 1-year, 3-year or 5-year estimates with Census 2000 data.

CheckedDifferences in the universe, question wording, residence rules, reference periods, and the way in which the data are tabulated can impact comparability with Census 2000.

Use our Table Comparison Lookup Tool to check for table-specific comparability.

ACS 3-year to 3-year and 5-year to 5-year?

The Census Bureau recommends that you:

CheckedDO compare similar period lengths, for example, 3-year to 3-year.

CheckedDON'T compare estimates from different period lengths, for example, 1-year to 3-year.

CheckedDO compare estimates from non-overlapping periods, for example, compare a 2005-2007 ACS 3-year estimate to a 2008-2010 ACS 3-year estimate.

CheckedDON'T compare overlapping periods, for example, the 2005-2007 ACS 3-year estimates to the 2006-2008 ACS 3-year estimates.

Tools and Resources

Table-specific Guidance

Use our Table Comparison Lookup Tool to search for a comparable table for your topic of interest. You can enter ACS table numbers or Census 2000 table numbers.

Topic-specific Guidance (by year)

Topic specific guidance is provided on a yearly basis:

Comparison Quick Guide (2009)

High-level guidance (compare, compare with caution, etc.) on groupings of topics (characteristics).

Source: U.S. Census Bureau | American Community Survey Office | Email ACS | Last Revised: March 17, 2015
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