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  Census >ACS Home > Using the Data > Quality Measures

How to Use the Data Main

ACS and Intercensal Population Estimates

Comparing ACS Data to Other Sources

Subject Definitions

Accuracy of the Data

Quality Measures
 >Sample Size:
     > Data
     > Definitions
 >Coverage Rates:
     > Data
     > Definitions
 >Response Rates:
     > Data
     > Definitions
 >Item Allocation Rates:
     > Data
     > Definitions

ACS Group Quarters
  » 2006 GQ Data Products

  » ACS 2000 Errata (11/7/02)
  » ACS 2000 Errata (3/25/02)

User Notes
  » ACS 1999 Limitations
  » ACS 2000 Notices

Geography Explanation

Data Products Details

Using Data from the 2006 ACS [PDF]

ACS Summary File
  » Technical Documentation


The Quality Measures sample size, coverage, and response data for 2007 and future years will only be available in the B98* series of Detailed Tables on American FactFinder (AFF).

Quality Measures data for 2006 and earlier years will remain on the ACS website and will not be added to AFF.

The quality measures provided in this section illustrate the steps the Census Bureau takes to ensure that ACS survey data are accurate and reliable.

1. How large was the sample used to produce the ACS estimates?

Sample Size:      
Sample Size Definitions
  3. What was the response to the survey?

Response Rates:      
Response Rates Definitions
2. How well does the ACS cover the population?

Coverage Rates:      
Coverage Rates Definitions
  4. How complete were the data used to produce a specific estimate?

Item Allocation Rates:      
Item Allocation Rates Definitions

The ACS produces survey data each year to measure key social, economic, and housing characteristics about the U.S. population. The four questions above identify four important aspects of survey quality. These quality measures are produced annually to accompany each ACS data release and describe the quality of those data. The quality measures are available at national and state levels. Clicking on "definitions" will provide additional information on each of these measures, including why the measure is important and how it was calculated.

Data for Puerto Rico are available starting with 2005. You can access the Puerto Rico data in two different ways. If you select the 'All States' view off the 'Select Nation/State' pick list, Puerto Rico data are shown at the bottom of the view. You can also select Puerto Rico directly at the bottom of the 'Select Nation/State' pick list. The numbers and rates for the United States do not include Puerto Rico.

Source: U.S. Census Bureau  |  American Community Survey Office  |  Page Last Modified: September 15, 2008