Household Surveys:American Community Survey

&American Housing Survey

Warren A. BrownFebruary 8, 2007

Outline

• Purpose• Target Population• Sampling Frame• Data Collection• Non-Response• Missing Data

• Weighting• Sampling Error• Access to Reports• …to Aggregate Data• …to Microdata• Research Questions

ACS: Purpose

• Key Component for Re-Engineered Census• Replacing the Decennial Census “Long-Form”• Continuous measurement rather than snapshot• Meet federal legislative and program needs• Other stakeholders in state and local

government and private sectors• Provide annual data on demographic, social,

economic and housing characteristics.• Proportions rather than counts

ACS: Target Population

• Current residence not “Usual Residence”– “two-month rule”

• Household population in 2005

• Total (HH + GQ) in 2006 and ….

• GQ residency is “de facto”

ACS: Sampling Frame

• Master Address File (MAF)– Official inventory of known living quarters– Linked to TIGER

• Housing Units– Based on Census 2000 MAF and updates from the

USPS’ Delivery Sequence File

• Group Quarters– … and updates from the administrative records and

the FSCPE– Excluded from ACS are domestic violence shelters,

soup kitchens, commercial maritime vessels,…

ACS: Design of the Sample

• Annual Sample Size of 3 million addresses• Series of Monthly Samples of 250,000 addresses• HU sample in each of the 3,141 Counties• Areas with smaller populations sampled at higher rates

than those with larger populations• HU Address sampling rate set by Block based on entity

(municipality, school district, tract) • Final sampling rate varies between 1.6% and 10%• No HU address can be sampled more than once in 5

years

ACS: Sample Design cntd

• GQ facilities sample for each state• Two stratum

– Small (15 or fewer residents)– Large ( more than 15 residents)

• Small – Data collected on all residents– Facility eligible once in 5 years

• Large– Groups of ten residents sub-sampled– Number of groups determined by size of facility– Facility eligible every year

ACS: Data Collection

• HU addresses by three modes – Mailout of paper questionnaire in 1st month– Telephone (CATI) non-response follow-up in

2nd month – Personal visit (CAPI) non-response follow-up

in 3rd month to a sub-sample

• GQ– Personal visit within 6 weeks of sample

selection

Data Collection Timetable

ACS: Questionnaire

• Content designed to meet the needs of federal government agencies

• 25 housing and 42 population questions (6 basic and 36 detailed)

• Household Respondent provides responses for all other residents of the household

• Householder or Reference Person is “Person 1”

ACS: Response Rates

• Participation is mandatory

• Sample addresses eligible for interviewing:– 51% Mail response– 9% CATI non-response follow-up– 38% CAPI non-response follow-up– 2% Non-interview

ACS: Missing Data

Item non-response or failed edit check• FEFU – failed-edit follow-up

– More than 5 household members– Critical questions not answered– 33% of mail return questionnaires in 2005

• Imputation– Assignment used other data on respondent– Allocation – hot deck procedure– Flags variables

ACS: Weighting

• Person and Housing Unit weights• Three stages

– Probability of selection (initial sampling rate)– Adjust for non-response– Control to Intercensal Population Estimates

• Sum the weights– Person weights for person characteristics– HU weights for family, household or housing unit

characteristics

• Householders = Households ???

ACS: Weighty Issues

ACS 2005 for United States

• 288,378,137 Persons in Households

• 111,090,617 Households

• 114,763,475 Householders

• Average Household Size– 2.60 based on Households– 2.51 based on Householders

ACS: Sampling Error

• Publishing margins of error in tables

• More sample less error

• 1, 3, and 5 year estimates and associated sampling error

• Sampling error for small area data

Access to Reports/Tables/Data

• ACS section of Census.gov

• American FactFinder

• ACS FTP Site

• ACS Data Tables

• ACS Public Use Microdata

www.census.gov/acs/www/

American Community SurveyProgram Schedule

• ACS Demonstration Period: 1996-2004– 2000-2004 data products: Summer, 2005

• ACS full implementation began January 2005– First full implementation data products: Summer,

2006– Annually updated data products every year

thereafter

Full Implementation

• 3 million addresses every year throughout the U.S. and in Puerto Rico

• Provide annual profiles for communities of 65,000 or more

• Provide 3- to 5-year cumulations for communities of less than 65,000 population

ACS Sample Design

Available Collection Sample

Now 2004Partial

Household

2006 2005 Full Household

2007 2006Full Household

& GQs

ACS “Long Form” Data by Geography

Available Geographic Areas

2006 County, Municipality > 65,000

2007 County, Municipality > 65,000

2008 County, Municipality > 20,000

2009 County, Municipality > 20,000

2010 All Municipalities, Tracts, BGs

ACS vs Traditional Census

Available ACS Old Census

2006 >65,000 N/A

2007 >65,000 N/A

2008 >20,000 N/A

2009 >20,000 N/A

2010 ALL N/A

2011 ALL N/A

2012 ALL ALL

ACS: Access to Aggregate Data

• Tabular data on American FactFinder

• Summary Files similar to SF3 being tested

ACS: Access to Microdata

• ACS 2005 PUMS on– American FactFinder– Data Ferrett

• Tabulated Estimates for User Verification

• ACS PUMS is a sub-sample representing 1% of total housing units

ACS: Research Questions