1 The American Community Survey An Update Pamela Klein American Community Survey Office Washington Metropolitan Council on Governments Cooperative Forecasting and Data Committee Washington, DC January 9, 2007

2 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

3 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.

Geographic Areas Type of Legal, Administrative, or Statistical Area Number included in 2005 ACS for the United States Number included in 2005 ACS for Puerto Rico Percent of All Such Areas Nation1--100% States (including DC and Puerto Rico) % Census Regions and Census Divisions % Congressional Districts % Urban/Rural State Components (excluding DC) % Public Use Micro Data Sample Areas 2, %

Geographic Areas Type of Legal, Administrative, or Statistical Area Number included in 2005 ACS for the United States Percent of All Such Areas Number included in 2005 ACS for Puerto Rico Percent of All Such Areas Metropolitan, Micropolitan and Combined Statistical Areas 61258%1169% Counties and Municipios77625%1215% School Districts9957%1100% Places4692%73% American Indian and Alaska Native Areas 152%-- Minor Civil Divisions1882%-- Other Geographic Areas3,9343%2453%

6 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

7 Margin of Error

8 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.

9 Using ACS Data ACS data are comparable to Census 2000 Comparing 2005 ACS data with 2004 ACS data Percentage distributions

10 Reference Materials ACS Data User Training Guide ACS Design and Methodology technical document Using Data From the 2005 ACS

11 Data Products Detailed Tables Data Profiles Narrative Profiles Ranking Tables Thematic Maps Geographic Comparison Tables Subject Tables Selected Population Profiles

12 Public Use Microdata Sample (PUMS)

User’s Guide

14 Thematic Maps

15 Data Profiles

16 Geographic Comparison Tables

17 Selected Population Profiles

18 Detailed Tables Using the “options” tab, you can display information by different geographic components, such as urban and rural.

19 For More Information American Community Survey Office U.S. DEPARTMENT OF COMMERCE U.S. Census Bureau Washington, DC ACS Alert