Panel on Statistical Methods for Measuring the Group Quarters

Population in the ACS

APDU

Paul R. VossUNC at Chapel Hill

& Panel Chair

APDU 2010 Annual ConferenceSeptember 21, 2010

Committee on National Statistics (CNSTAT)

• Established in 1972 at the National Academies to improve the statistical methods and information on which public policy decisions are based

• Carries out studies to foster better measures of the economy, crime, poverty, and other domains

• Evaluates ongoing statistical programs and coordination of the decentralized U.S. federal statistical system

• Activities generally requested and sponsored by specific federal statistical agencies

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Some recent CNSTAT reports addressing census & ACS topics

• W.A.V. Clark, UCLA• S. Copella, PA SDC• D.Dolson, Statistics

Canada• R. Folsom, RTI

International• R. Harter, NORC

• S. Heeringa, University of MI

• J. Salvo, NYC Dept. of City Planning

• R. Valliant, Univ. of MD• P. Voss, UNC (Chair)• K. Marton, CNSTAT

(Study Director)

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Panel on Statistical Methods for Measuring the Group Quarters Population in the ACS

• Duration: Approximately 18-20 months– 6 meetings– workshop & other activities– interim & final report

• Charge: In depth review to advise Census Bureau on measuring GQ in ACS– statistical & operational issues

• sample frame• sampling• weighting & population controls

– data use/user issues• who?• how?• Alternatives?

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Panel on Statistical Methods for Measuring the Group Quarters Population in the ACS

We need to know…

• Why? Basis of objection? If this is you or your organization… we really want to hear from you!

• Note:– I’m asking this question in my role as chair of the Panel– The Panel has not yet discussed this question in any serious way

• But we recognize that there are some very serious issues here…

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WHO WOULD OBJECT IF OUR PANEL RECOMMENDED TO THE CENSUS BUREAU THAT SOME OR ALL GQ SUBPOPULATIONS BE PLACED “OUT-OF-SCOPE” IN THE ACS?

Issues…• Early indications suggest that there are few users of

the ACS GQ data, per se• Why would this be?

– not much data available yet from ACS– the eventual ACS data for GQ populations is going to be pretty thin– 2010 Census data showing GQ populations by type and age-sex-race

characteristics may be sufficient – there are many other special surveys of GQ populations designed to

meet federal data & programmatic needs– there are problems with the ACS GQ data

• But what happens if the GQ were not included in the total population universe? Let me reframe the Q:

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WHO WOULD OBJECT IF SOME OR ALL GQ POPULATIONS WERE REMOVED FROM THE TOTAL BASE POPULATION FOR ACS DATA

ON POPULATION CHARACTERISTICS?

Let’s back up for just a moment

…places where people live or stay, in a group living arrangement, that are owned or managed by an entity or organization providing housing

and/or services for the residents

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What are “group quarters”?

7 main types of GQ• Correctional facilities for adults• Juvenile facilities• Nursing facilities/skilled nursing facilities• Other health care facilities• College/university student housing• Military quarters• Other noninstitutional facilities

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3 principal types of GQ comprise most of GQ universe

• College/university student housing (25%)• Nursing facilities/skilled-nursing facilities (23%)• Correctional facilities for adults (19%)• Full GQ population approximately 8 million

persons (~3% of total population)

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Background• The census enumeration and the separate

identification of persons living in irregular housing dates from 1850

• GQ: part of the census sample data collection and reporting since 1940

• Comprehensiveness of tabulations and quality of the sample data has varied from census to census

• GQ in ACS monthly sample since 2006

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Why retain GQ data in the ACS?• Because the Bureau promised!• Since 1970, the long from sample has provided content

rich & statistically very strong data for the full U.S. population; important programmatic needs

• Because the ACS GQ data, in some respects, are much improved over the 2000 Census long form GQ data– e.g., significantly reduced levels of item imputation

• Because some data users may need these data– some data users may need certain GQ data for programmatic

purposes

– many data users want the ACS universe to include the total population

– we want to hear from those users

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Why consider dropping some or all GQ data from the ACS?

• The need for sample GQ data is not very well documented• Not much is going to be published anyway

– But what about the PUMS data?

• There are problems with the data:– Imputation rates still uncomfortably large– The separation of the sample controls from the census enumeration

means that controls are estimate-based– Small populations; smaller samples; “zero” GQ problems

• Some small, difficult-to-survey, GQ populations have already been dropped from the ACS sample

• Are there appropriate cost-benefit issues? GQ considerably more expensive than HH portion of ACS (GQ: $89 per person interview; HH: $13 per person interview)

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We really want to hear from you!• You may write to us directly expressing

your concerns or opinions– Paul Voss

• paul_voss@unc.edu– Krisztina Marton

• KMarton@nas.edu

• Survey of data users• Data user conference• It’s important!

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