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Greg Harper

Population Division

September 28, 2006

Presented to FSCPE Fall Meeting

Reviewing Subcounty Population Estimates

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Overview

• Subcounty population estimates methodology

• Review of housing unit data• Review of subcounty population estimates

Subcounty Population Estimates Methodology

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

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Housing Unit Estimates Equation

HU06 = HU00 + (NC06 + NM06) – HL06

HU06 = Estimated 2006 Housing Units

HU00 = 2000 Housing Unit Estimates Base

NC06 = Estimated New Residential Construction: 2000 - 2006

NM06 = Estimated New Residential Mobile Homes: 2000 - 2006

HL06 = Estimated Residential Housing Loss: 2000 - 2006

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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

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Mobile Home Placements

• State mobile shipments data distributed to subcounty areas based on the subcounty area’s share of mobile homes in Census 2000

• Sample data retabulated for consistency with 100 percent housing unit data

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Housing Unit Loss Housing Unit Loss

• Data derived from 1997–2003 AHS National Sample• Type of Non-interview Considered a Loss

– Type B, 16 - Interior exposed to the elements– Type C, 30 – Demolished or disaster loss– Type C, 31 – House or mobile home moved

• Categories for Developing Loss Rates– Mobile Homes– Age of Structure (seven categories)

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Summary of Loss RatesSummary of Loss Rates

• 0.295% Total Annual Loss Rate• Mobile Homes: 1.580%• Houses or Apartments

– 1990-2000: 0.058%– 1980-1990: 0.092%– 1970-1980: 0.100%– 1960-1970: 0.178%– 1950-1960: 0.224%– 1940-1950: 0.359%– Pre-1940: 0.395%

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Uncontrolled Subcounty Population Estimate

UHHP06 = HU06 * OCC00 * PPH00

UHHP06 = Uncontrolled 2002 subcounty household population estimate

HU06 = 2006 Housing Unit Estimate

OCC00 = Census 2000 occupancy rate

PPH00 = Census 2000 population per household

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Final Subcounty Population Estimate

SCPOP06 = [UHHP06 * (ARCHHP06/HUMHHP06)] + GQ06

SCPOP06 = Final 2006 subcounty population estimate

UHHP06 = Uncontrolled 2006 household population estimate

ARCHHP06 = 2006 Administrative Records method county household population estimate

HUMHHP06 = 2006 Housing Unit method county household population6 estimate

ARCHHP06/HUMHHP06 = Rake Factor

GQ06 = 2006 group quarters population estimate

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The Housing Unit Review File

• File contains components of housing unit change

• Available in late October

• Two months of review

• Can be made available to local governments

• Data for areas affected by Katrina

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Housing Unit Review File Components

• PER7_2005 = building permits issued in calendar year 2004 * .98

– Assumes six-month lag time between permit issuance and completed construction

– Assumes 2 percent of permits do not result in completed construction

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Housing Unit Review File Components

• MOB7_2005 = New mobile homes allocated to place from July 1, 2004 to July 1, 2005

• NPHB7_2005 = Nonpermitted residential construction allocated to place from July 1, 2004 to July 1, 2005– If permits are issued for locality, NPHB will be 0

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Housing Unit Review File ComponentsHousing Unit Review File Components

• NPHD7_2005 = Estimated housing unit loss from July 1, 2004 to July 1, 2005– The same loss rate is applied to updated estimates of

housing units so the amount of loss will not change much from year to year

• HSG7_2005 = 2005 estimate of housing units

• HSG7_2005 = HSG7_2004 + PER7_2005 + MOB7_2005 + NPHB7_2005 – NPHD7_2005

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Housing Unit ReviewHousing Unit Review

• Use Excel spreadsheet in same format

• Keep housing units consistent with components

• Route local comments through FSCPE agency

• Provide comments in lowest level of geography– Summary level 157 in non-MCD states, 071 in MCD states

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The Subcounty Population Estimates Review File

• File will be made available In February

• Three to four weeks for review

• File can not be shared with local governments

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Subcounty Population Estimates Review File

• VACR_2000 = Census 2000 Vacancy Rate

• PPH_2000 = Census 2000 Population per Household

• HU_2005 = 2005 Housing Unit Estimate

• GQ_2005 = 2005 Group Quarters Population Estimate

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Subcounty Population Estimates Review File

• HHPOP_2005 = 2005 subcounty population estimate– HHPOP_2005 = HU_2005 * PPH_2000* ((100 –

VACR_2000)/100) * RAKE_2005

• POPCEN_2000 = Census 2000 total population

• PBASE_2000 = 2000 Estimates base population– Census 2000 population updated with County Question

Resolution Actions, boundary changes, and administrative geographic revisions.

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Subcounty Population Estimates Review File

• POP_2005 = HHPOP_2005 + GQ_2005

• RAKE_2005 = County population estimate/ county sum of uncontrolled subcounty housing unit population estimates– A rake factor less than 1 indicates faster housing

unit growth than population growth

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Subcounty Population Estimates Review

• Comments should be as specific as possible– Most changes should have already been made to

the housing unit file – If housing units are OK and the county estimate is

OK then problems should be limited to GQ or calculations

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Questions ?