U.S. Census Bureau’s Population Estimates Program

Victoria VelkoffPopulation DivisionU.S. Census Bureau

APDU 2010 Annual Conference Public Data 2010: Opportunities and Challenges for the New Decade

September 20, 2010

This presentation is released to inform interested parties of research and to encourage discussion. Any views expressed on statistical, methodological, technical, or operational issues are those of the author and not necessarily those of the U.S. Census Bureau.

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Outline

• Population estimates produced

• Uses and methods

• Challenge program

• Critical population estimates projects

• Estimates evaluation

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Annual Estimates • Population

– Nation by age, sex, race, and Hispanic origin – States by age, sex, race, and Hispanic origin– Counties by age, sex, race, and Hispanic origin– Incorporated places and minor civil divisions (total

population only)– Puerto Rico Commonwealth and municipios by

age and sex

• Housing units– States– Counties

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Uses of Population Estimates• Allocation of over $400 billion in federal funds each year

• Controls for surveys– Current Population Survey– American Community Survey– Survey of Income and Program Participation– American Housing Survey

• Denominators for statistical rates– Birth and death rates (NCHS)– Per capita income (BEA)

• Other Federal Uses and Program Planning – Department of Education, National Cancer Institute– Location of public and private services

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Current Methods National level:

Cohort-component method (also called ADREC)

P2 = P1 + B - D + NIMNIM = Net international migration

State and county level:Cohort-component method

P2 = P1 + B - D + NM NM = Net domestic and international migration(controlled to the national estimates)

Subcounty level:Distributive housing unit method

County population is distributed to subcounty parts based on updated estimates of housing(Controlled to county estimates)

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Population Estimates Challenge Program

• Challenges– An alternate population estimate provided

by the governmental unit – Usually based on the housing unit method– Usually accepted by the Census Bureau

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Housing Unit Method(as used in the 2000s Challenge Process)

Populationt = HUt * PPHt * Ot + GQt

Where:

HU = Number of housing units

PPH = Persons per household (Census 2000 value)

O = Occupancy rate (Census 2000 value)

GQ = Group Quarters population

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Challenge Program Suspended

• In 2010, we suspended the challenge program until 2012.

• Plan to evaluate the challenge results during our estimates evaluation.

• Housing unit method tends to have an upward bias if persons per household or occupancy not updated.

• We will re-engineer the process before we reinstate it.

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Population Estimates Critical Projects: 2010 through 2012

• Production for Vintage 2010 estimates• Demographic Analysis (DA) • Production of Intercensal Estimates• Estimates Evaluation (E2)• Research and production of Vintage 2011

• Released starting December 2011• Will use the current methods

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Production of Vintage 2010

• Not released to the public – Census data come out starting in December

• Production for this set of estimates has started

• Needed for – • CPS controls • Intercensal estimates (ACS controls)• Estimates evaluation

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Postcensal Versus Intercensal Estimates• Postcensal population estimates

– Built off of the last census– “Vintage” identified by terminal year in the series– July 1 estimates, full series from last Census date forward

(for Vintage 2009, series is April 1, 2000-July 1, 2009)

• Intercensal population estimates– Based on two consecutive censuses and the postcensal

estimates– Distributes the difference between the postcensal

estimate for April 1, 2010 and the Census 2010 count back through time

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Intercensal Estimates

• We are producing intercensal estimates at the county level by age, sex, race, and Hispanic origin.

• Timing• We receive Census 2010 data in March 2011• Estimates are due to ACS as controls by mid-May

2011• Issues

• Timing• Katrina and Rita affected areas?• Level of detail in the estimates • We may revise the intercensal estimates post 2011

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Population Controls Provided to ACS

• Population estimates provided as controls– County by age (single years 0-84, 85+),

sex (male, female), race (31 race groups), and Hispanic origin (Hispanic, non-Hispanic)

– Puerto Rico municipios by age (single years 0-84, 85+) and sex

– For ACS 2009 – subcounty total population estimates

• Group quarters population by the 7 major types at the state level and for Puerto Rico

• Housing units at the county level and subcounty level

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Population Controls by ACS Release Year: 2011

ACS Data Year of Pop Control Release Year

2010 ACS July 1, 2010 controls from the Intercensal Estimates at the county level (based on Census 2000 and Census 2010)

2011

2008-2010 ACS

Average of July 1, 2008-2010 Intercensal Estimates at the county level

2011

2006-2010 ACS

Average of July 1, 2006-2010 Intercensal Estimates at the county level

2011

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Population Controls by ACS Release Year: 2012

ACS Data Year of Pop Control Release Year

2011 ACS July 1, 2011 controls from Vintage 2011 (Census 2010 base)

2012

2009-2011 ACS

Average of July 1, 2009-2011 controls based on Intercensal Estimates and Vintage 2011 (Census 2010 base)

2012

2007-2011 ACS

Average of July 1, 2007-2011 controls based on Intercensal Estimates and Vintage 2011 (Census 2010 base)

2012

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To evaluate the performance of the methods we currently use to produce population estimates and to evaluate alternative methods relative to the Census 2010 counts.

Goal of Estimates Evaluation (E2)

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We evaluate our population estimates against the census counts to:

• Further our understanding of the accuracy of our estimates.

• Be able to compare the accuracy of our estimates to the accuracy of estimates produced using alternative methods.

• Make a decision post-2010 about methods we will use in the future.

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Estimates Methods to be Evaluated

• Census Bureau will evaluate– Cohort-component method (national,

state, and county)– Housing unit method (national, state,

county, and subcounty)

• External researchers will evaluate– Ratio correlation method (county)– Component of change (subcounty)– Housing unit method (county)

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• The Production and Evaluation of Estimates of the Population Produced From Multiple Indicators of Population Size and/or Growth – 3 contracts

• The Production and Evaluation of Estimates of the Total Population at the County Level Using a Housing Unit Based Method – 2 contracts

• The Production and Evaluation of Estimates of the Total Population at the Subcounty Level Using a Component of Change Method – 2 contracts

External Research Topics

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Estimates for Evaluation

• Vintage 2010 estimates including challenges? • A “pure” cohort component method

(i.e., no challenges)?• Resident population or household population

and estimates of GQ?• Demographic characteristics:

– Full detail or limited?– What geographic level?

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Estimates Evaluation: Key Points

• Focus resources on the most promising alternatives

• Provide the most comprehensive evaluation possible given the resource limitations

• Make evaluation estimates available to the public• Collaborate with FSCPE members and other

external researchers • Use production requirements and underlying

principles to guide our decisions

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Contact information:

• Victoria Velkoff– E-mail: victoria.a.velkoff@census.gov– Tel: 301-763-7070

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