The AmericanCommunity Survey (ACS)

Lisa Neidert

NPC Workshop: Analyzing Poverty and Socioeconomic Trends Using the American Community Survey

June 22 – June 26, 2009

What is the ACS?

A large, continuous survey Produces single and multiyear estimates of

the characteristics of the population and housing

Produces information for small areas including tracts, block groups and population subgroups

Key component of the decennial census program

Origins of the ACS

More timely data Operational reasons

Steadier funding Year-round Interviewing

Skilled interviewers instead of temps

Strengthen Decennial Census Improved census geography

Updated address files

More timely data

Mariel Boat Lift Natural disasters

More timely data . . .

Communities Populations

ACS Implementation

Demonstration Period 1996-2004

ACS Implementation

Full implementation: 2005* Every county nationwide Products released in 2006 Annual updated data products released

every year thereafter

*Did not include group quarters in 2005

Data Release Timetable

Sample Specifics

3,000,000 addresses 250,000 a month

ACS Operations: Mixed Mode

ACS Operations

Combination of Modes: October 2006 sample panel

Workloads and Costs by Mode

ACS is mandatory

Survey Response

Distribution of Interview OutcomesVariation in Selected States

Interpreting ACS data

Universe and Residence Rules Time periods Reference periods

Comparison Guidelines http://www.census.gov/acs/www/UseData/compAC

S.htm

ACS Compass Products Appendices

ACS Universe

Total resident population of the United States

Group Quarters population added to the sample in 2006

Example Ann Arbor, MI, 2006: 112,371 Ann Arbor, MI, 2005: 98,743 Ann Arbor, MI, 2000: 114,024

Residence Rules

Resident of the housing unit if: Lives there year round Lives there more than 2 months but not year round Is living there now with no other place to live Is away now for 2 months or less

Not a resident of the housing unit if: Lives there 2 months or less with another

residence Is away now for more than 2 months

Reference Periods

ACS uses the interview data as the single reference point, or as the end of a reference period, for all data collection Interviewed in October 2006

Earnings reference period: October 1, 2005 – September 30, 2006

Data Products: Annual

Tabular Profiles Narrative Subject Geographic Comparison Ranking Detailed

Data Products Annual

Microdata 1%

~1,300,000 housing records ~3,000,000 person records

Microdata are a sample of the ACS respondents Approximately 65 of 100 Confidentiality measure

Data Products Multi-year

Combines 3 years worth of data, with a few modifications to the underlying data

Summary data GQ population is estimated for 2005 Geographic boundary changes reflected for all

years

Microdata Re-weight Index income

Data Products: Multi-year

3-year: 2006 - 2008 Release dates: August 2009+

Multiyear Estimates Study 5-year; 3-year; 1-year For test communities only

34 counties

http://www.census.gov/acs/www/AdvMeth/Multi_Year_Estimates/overview.html#noteforusers

Microdata vs Tabular

Census Bureau website emphasizes tabular data via American FactFinder FTP is interface to microdata

Exceptions

Workshop Micro (65%) Tabular (35%)