AN OVERVIEW OF POPULATION ESTIMATES

1
AN OVERVIEW OF POPULATION ESTIMATES

• Katie Wengert
• Population Estimates Branch
• Spring 2008 SDC Meeting
• April 16, 2008

2
Overview

• General concepts
• Federal mandate
• Estimate products
• Data availability
• Uses of estimates
• General methods
• Data sources
• An example State and county totals

3
General Concepts

• Demographic characteristics
• ASRH age, sex, race, and Hispanic origin
• Population universes
• Resident
• Civilian and Military
• Household and Group Quarters
• Institutionalized and Noninstitutionalized
• Civilian Noninstitutionalized (CNI)

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General Concepts (cont.)

• Vintages
• Revise whole time series annually
• Take advantage of the most recent input data
• Make sure whole time series is consistent
• Method
• Assumptions
• Input data
• Geography

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Federal Mandate

• The Intercensal Estimates Program is required
• under U.S.C. Title 13, Section 181
• During the intervals between each census of
  populationthe 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 fifty
  thousand 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.

6
Estimate Products

• National population by ASRH (monthly)
• State and county population totals
• State population by ASRH
• County population by ASRH
• Local government population totals
• Commonwealth of Puerto Rico population by age and
  sex
• Puerto Rico municipio population by age and sex
• State and county housing unit totals

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Data Availability

• December
• January
• Spring
• Summer

• National, state, Puerto Rico totals
• State Puerto Rico 18 population
• County municipio totals
• National, state, Puerto Rico demographic detail
• Subcounty totals
• State county housing units
• County municipio demographic detail

8
Uses of Estimates

• Allocation of over 300 billion in federal funds
  to state and local governments each year
• Controls for federal surveys
• Current Population Survey
• American Community Survey
• Survey of Income and Program Participation
• American Housing Survey
• Denominators for statistical rates
• Birth and death rates
• Per capita income
• Public and private program planning

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General Methods

• National population estimates
• Cohort-component method
• P2 P1 B D NM
• Where
• P2 Population at time 2
• P1 Population at time 1
• B Births
• D Deaths
• NM Net international migration

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General Methods (cont.)

• Subnational population estimates
• State and county totals
• Component method
• State and county characteristics
• Cohort-component method
• Subcounty level
• Distributive housing unit method

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General Methods (cont.)

• Consistency across estimates products
• All estimates for lower levels of geography add
  to higher levels of geography
• All estimates by characteristics add to totals
  and to estimates by characteristics at higher
  levels of geography

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Data Sources

• Base population
• Census 2000 modified by race
• Updated with Count Question Resolution (CQR) and
  other geographic changes
• Vital statistics
• National Center for Health Statistics (NCHS)
• Federal-State Cooperative Program for Population
  Estimates (FSCPE)
• Domestic migration
• Internal Revenue Service (IRS) (Title 26
  protected)
• Social Security Administration
• Medicare

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Data Sources (cont.)

• International migration
• Immigration Statistics Staff U.S. Census Bureau
• Three subcomponents
• Net movement to and from Puerto Rico
• Net native emigration
• Net foreign born migration

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Data Sources (cont.)

• Group Quarters population
• Census 2000
• FSCPE
• Department of Defense
• Department of Veterans Affairs
• Military population and overseas movement
• Department of Defense

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State and County Totals General Processing
Concepts

• Geography
• Produce estimates at the county level
• Sum the counties to estimate the state
  populations
• Time
• Calculate population estimates for one year at a
  time
• Use each estimate as the base population for the
  subsequent estimate

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State and County Totals General Processing
Concepts (cont.)

• Age
• Estimate the under age 65 and 65 populations
  separately, due to different migration data
  sources for each population
• Add the under age 65 and 65 populations to get
  total population

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State and County Totals Method

• Start with the base population
• Census 2000 modified race population
• Retabulated to represent current geography
• Includes CQR and other geographic changes
• Subtract the GQ population to get the household
  base population

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State and County Totals Method (cont.)

• Calculate the household population estimate
• Add the births and subtract the deaths from the
  household base population
• Add the net domestic migration and the net
  international migration
• Add the military movement (to the under age 65
  population only)
• Add the GQ population to the household population
  estimate to calculate the resident population
  estimate

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Domestic Migration Under age 65

• Match 2 years of IRS tax returns by individuals
  Protected Identification Key (PIK)
• Compare the 2 addresses to identify movers
  non-movers
• Calculate county net migration rates
• Calculate the migration base
• Migration Base Population ½ (Births Deaths
  Net International Migration)
• Apply net migration rates to the migration base
  to get net migrants
• Add net migrants to household base population

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Domestic Migration 65 Population

• Calculate Medicare migration rates based on
  coverage rates and the change in enrollment
• Calculate the migration base
• Migration base Population ½ (Puerto Rico
  movement Net native emigration Deaths)
• Apply the migration rates to the migration base
  to get net migrants
• Add the net migrants to the base population

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State and County Totals Incorporating Local
Information

• Challenges
• Special Censuses
• Estimates review by FSCPE members

22
Contact Information

• Estimates
• http//www.census/gov/popest/estimates.php
• Katie Wengert
• katrina.l.wengert_at_census.gov