The Intercensal Population Estimates and Projections
Program
Signe I. Wetrogan
Assistant Chief for Population Estimates and Projections
Presented to Metropolitan Washington Council of Governments
Washington, DC
June 7, 2005
Intercensal Estimates Program
Required under Title 13, Section 181 - US Code
“During the intervals between each census of population…the Secretary, to the extent feasible, should annually produce and publish for each state, county, and local unit of general purpose government which has a population of 50,000 or more, current data on total population and population characteristics, and to the extent feasible, shall biennially produce and publish for other local units of general purpose government current data on total population.”
Population Estimates
• National population estimates–Monthly by age, sex, race, and Hispanic origin
• State population estimates–Annually by age, sex, race, and Hispanic origin
• County population estimates–Annually by age, sex, race, and Hispanic origin
• Functioning governmental units–Annually by total population for 39,000+ governmental entities
• School Districts–Annually by total population
Housing Unit Estimates
• State Estimates of Housing Units–Annually
• County Estimates of Housing Units–Annually
Population Projections
• National Projections Current Interim projections – age, sex, selected race/Hispanic
Origin groups
Periodically prepared
• State Projections Current interim projections – age and sex
Periodically prepared
Uses of Population Estimates
• Allocation of over $200 billion in federal funds
annually• Controls for federal surveys
–Current Population Survey–American Community Survey
• Denominators for statistical rates–Birth and death rates–Per capita income
• Number of Senate clerk hires• Program planning
–Location of public and private services
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Methodology
National, state, and county levels:Component method
P2 = P1 + B - D + NM
Subcounty level:Distributive housing unit method
County population distributedto subcounty parts based onupdated estimates of housing units
U.S. Pop. Total(Cohort-Component Method)
State Pop. Total
County Pop. Total(Component Method)
Controlled To
Totaled To
Controlled County Pop. Total
All Estimates Must Be Consistent
Sub-County Pop. Total(Distributive Housing Unit Method)
Distributed To
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National Methodology
National Methodology P2 = P1 + B - D + NM
Beginning PopulationCensus 2000 as enumerated
Births and DeathsRegistered births and deaths withdemographic characteristics fromNational Center for Health Statistics(Receive micro records)
P2 = P1 + B - D + NM
Subcounty level:Distributive housing unit method
County population distributedto subcounty parts based onupdated estimates of housing units
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National Methodology
International Migration Net movement of the foreign-born population
Developed from annual change in foreign-born population as measured by the American Community Survey (ACS)
Net movement between the US and Puerto Rico
Measured by the Census 2000 Emigration of native-born population
Measured by the Census 2000
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State/County Methodology
Administrative Records Component of population change method
P2 = P1 + B - D + NM
Done in cooperation with Federal State Cooperative Program for Population Estimates (FSCPE)
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The Federal-State Cooperative Program for Population Estimates (FSCPE)
In 1973 the Federal-State Cooperative Program for Population Estimates was formalized. The FSCPE was formed to:
• Promote cooperation between states and the Census Bureau• Prepare a set of consistent county and subcounty estimates• Improve and advance estimates methodology • Enhance the recognition of local demographic work
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The Federal-State Cooperative Program for Population Estimates (FSCPE)
District of Columbia contact:Mr. Robert BeaslyData Services DivisionD.C. Office of Planning
Maryland contact:Mr. Hal Sommers Vital Statistics AdministrationDept. of Health and Mental Hygiene
Virginia contact:Dr. Julie Martin Cooper Center for Public ServiceUniversity of Virginia
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State and County Component Method
Births anddeaths
(NCHS, FSCPE )
Population(Census
2000)
InternationalMigration
(ACS, Census
2000)
InternalMigration
(IRS)
InternalMigration
(SSANUMIDENT)
Medicare(CMS)
GroupQuartersUpdates(FSCPE)
State and County Estimating System
DisseminationProducts
Monthly Survey
ControlsDenominators
Media andGovernment
BriefingTables
AnalyticalTables
Estimates of County HH Pop Under 65
HHP=Household PopulationNI=Natural IncreaseNMIG=Net Domestic MigrationNETMOVE=Net Movement from Abroad
HHP2 =
FSCPE
NCHS
+ NI
Tax returnbased rate
+ NMIG
Net movement ofForeign-bornpopulation
Emigration
Net movement betweenUS and Puerto Rico
+ NETMOVE
Persons Aging from
age 64 to age 65
- AGE
Last year’s estimate
HHP1
16
Natural Increase
Births and DeathsNational Center for Health Statistics (NCHS)
Data provided by State FSCPE representative
17
Net Movement from Abroad
Distribution of total US estimates to states/countiesDistribute total US estimates of net movement of foreign-born
Use Census 2000 state/county distribution of foreign-born, noncitizens, who entered the US in the last 5 years
Distribute total US estimates of net movement to and from Puerto Rico
Use Census 2000 state/county distribution of population who entered the US from Puerto Rico in last 5
yearsDistribute total US estimate of emigration of native-born population
Use Census 2000 distribution of population
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Development of Net Migration for Population Under age 65 - Overview of Annual IRS File
Receive file in October of each year
Contents used in migration processing– Address, including ZIP code + 4
• Address as of when the return was filed– Number of exemptions by status– Number of dependents by status– SSN of filer and dependents– Name on tax return
19
Initial Processing of IRS Data Files
Match records from prior year file to current year file using filer’s modified SSN
Drop records that:– Do not match
• Filer must have returns for two consecutive years
– Have “deceased” in name fieldAssume address on tax file is residence of tax filer and
exemptions
20
Initial Processing Geocode records to state/county
– Use zipcode +4 to state/county coding guide
Compare geocodes for matched returns
If geocodes in time 1 and time 2 are different, the filer and exemptions on the return have migrated:
– Have county of residence in year 1
– Have county of residence in year 2
If geocodes in time 1 and time 2 are same, the filer and exemptions on the return are nonmigrants
Under age 65 exemptions are used
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Calculate Net Migration Rate
Tabulate for each county:
Outmigrants
Number of under age 65 exemptions there in year 1 and in different county in year 2
Inmigrants
Number of under age 65 exemptions there in year 2 and in different county in year 1
Nonmigrants
Number of under age 65 exemptions there in year 1 and year 2
22
Calculate Net Migration Rate
Net migration rate =
In-migrants – out-migrants /
non-migrants + out-migrants
23
IRS Data Confidentiality
Title 26 – protects the confidentiality of IRS data– No individual record data can be released
– Any publicly released data must go through suppression
– SSNs are modified
– Internal access to IRS is severely restricted
24
Develop Internal Migration Estimates for the Household Population
The net migration rate (derived from IRS data) is then applied to the household population under age 65
This results in an estimate of net internal migration for the population under age 65
Similar estimates are developed for the population over age 65 derived from Medicare data
Estimates of Group Quarters Population
Types: Institutional Correctional Facilities
Juvenile Facilities Nursing Homes Other Non- Institutional Colleges & Universities Military Quarters Other
• Change in Group Quarters population is tracked through an annual report prepared by the FSCPE
• Additional data are collected from the DOD and the VA
• This change is applied to the Census 2000 GQ count
COUNTY TOTAL POPULATION = HHP0 <65 + HHP65+ + GQ
State and County Component Method
• Control this population to the National estimate
• Sum the controlled county population for each state
• Distribute the controlled county population to the subcounty level
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Subcounty Distributive Housing Method
Housing Unitsand
Population(Census 2000)
BuildingPermits
(Census)
BASData
(Census)
Vacancy/PPH
(Census 2000)
Group QuartersUpdates(FSCPE)
SpecialCensusOutputs
County PopulationEstimates
(State/CountySystem)
Subcounty Estimating System
DisseminationProducts
HUDFunds
Allocation
MSADesignation
Updates
Media andGovernment
BriefingTables
AnalyticalTables
Place and County Subdivision Population Estimates
Distributive Housing Unit Method
Change in Housing Units since the last Census at the subcounty level is used to distribute the estimated county population
Components of Housing Unit Change
• Residential Construction• Mobile Home Placements• Housing Unit Loss
Subcounty Group Quarters data are taken from the same source as county Group Quarters data
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Housing Unit Estimates Equation
HU2 = HU1 + (NC + NM) - HL
HU = Housing Units
NC = Estimated New Residential Construction
NM = Estimated New Residential Mobile Home Placements
HL = Estimated Residential Housing Loss
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Estimated Residential Construction
Building permits– Compiled by the Census Bureau’s Manufacturing
and Construction Division (MCD)
Nonpermitted construction– Estimated from Annual Survey of Construction and
Census 2000 data
31
Mobile Home Placements
State mobile home shipment data distributed to subcounty areas based on the subcounty area’s share of state’s mobile homes
Mobile home data are no longer a 100% Census item
32
Housing Unit LossBased on data from 1997-2003 American Housing Survey (AHS)
3 types of noninterviews:Interior exposed to the elements
Demolished or disaster lossHouse or mobile home moved
Housing unit loss rates developed based on:Structure typeAge of structure
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Subcounty Housing Units = Residential Construction + Mobile Home Placements - Housing Unit Loss
Subcounty Distributive Housing Unit Method
• Use each subcounty area’s HU based household population estimate to distribute the county household population
Household population = (HU –vacants)* PPHVacants = Census 2000 ratePPH = Census 2000 persons per occupied housing unit
• Add the Group Quarters Population
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Population Projections Methodology
National and state -Component method
P2 = P1 + B - D + NM
Projections - not forecastsOutcomes of mathematical modelAssume recent demographic trends continue
Further Information
Population Estimates Web Sitehttp://www.census.gov/popest/estimates.php
Population Projections Web Sitehttp://www.census.gov/population/www/projections/popproj.html
Signe Wetrogan
Assistant Chief for Population Estimates and Projections
(301) 763-2093