The American Community SurveyAn Update Pamela Klein American Community Survey Office Washington Metropolitan Council on Governments Cooperative Forecasting and Data Committee Washington, DC January 9, 2007
Purpose of the ACS • Collect detailed Census sample data every month instead of only once each decade • Release tabulations of these data on a yearly basis • Restructure and simplify the 2010 Census
Release schedule for the ACS Data Products Data products are released in the year following the single-year or multi-year period in which data are collected.
Sampling Error • Sampling error occurs when estimates are derived from a sample rather than a census of the population. • Standard error is an estimate of the precision of the estimates. • The margin of error describes the precision of the estimate for a given confidence level and standard error. • Tools used to prevent incorrect conclusions
Statistical Significance • Small differences may be insignificant. • To do statistical testing of two estimates, you must calculate the standard error of the difference of the estimates. • Two estimates are "significantly different" if their difference is large enough that there was a less than 10 percent chance that the difference was purely random.
Using ACS Data • ACS data are comparable to Census 2000 • Comparing 2005 ACS data with 2004 ACS data • Percentage distributions
Reference Materials http://www.census.gov/acs/www/ • ACS Data User Training Guide • ACS Design and Methodology technical document • Using Data From the 2005 ACS
Data Products • Detailed Tables • Data Profiles • Narrative Profiles • Ranking Tables • Thematic Maps • Geographic Comparison Tables • Subject Tables • Selected Population Profiles
Public Use Microdata Sample (PUMS) http://factfinder.census.gov/home/en/acs_pums_2005.html
2005 User’s Guide http://www.census.gov/acs/www/Products/users_guide/index.htm
Using the “options” tab, you can display information by different geographic components, such as urban and rural. Detailed Tables
For More Information American Community Survey Office 1-888-346-9682 firstname.lastname@example.org www.census.gov/acs/www ACS Alert http://www.census.gov/acs/www/Special/Alerts.htm U.S. DEPARTMENT OF COMMERCE U.S. Census Bureau Washington, DC 20233