THE USE OF CADASTRAL DATA TO ESTIMATE SUB-COUNTY POPULATIONS

Jim SylvesterBureau of Business and Economic Research

The University of Montana-Missoula

The ProblemMany sub-county places are outside incorporated areas

– Census Designated Places (CDP)– School districts– Indian Reservations– Planning districts

How can one estimate population of sub-county areas without building permit data?

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Definitions

• CAMA (Computer Assisted Mass Appraisal) data sets contain standardized set of characteristics including age and type of structure so that comparisons of property assessments can be made.

• A cadastral map shows political and surveyed boundaries as well as ownership of land parcels.

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

CAMA Housing Units vs. Building Permits

Okaloosa, FL

Osceola, FL

Marion, FL

Sumter, FL

Lewis & Clark, MT

Missoula, MT

Flathead, MT

Spokane, WA

Gallatin, MT

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

POP t HUt PPH t OCC_RATE t= * * GQ t+

Housing Unit Method Equation

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Uncontrolled Household Population

Place 1 PPHHousing Units

OccupancyRate* * = Household Population

Place 1

Place 2 PPHHousing Units

OccupancyRate* * = Household Population

Place 2

Place 3 PPHHousing Units

OccupancyRate* * = Household Population

Place 3

Place 4 PPHHousing Units

OccupancyRate* * = Household Population

Place 4

Uncontrolled CountyHousehold Population

+

+

+

=

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

WEIGHT Control Household Population

Uncontrolled Household Population

= /

Controlling to Official Estimate

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Place 1

Place 2

Place 3

Place 4

Controlled CountyPopulation

+

+

+

=

* =Uncontrolled

Household PopulationPlace 1

WEIGHT Controlled PopulationPlace 1

* =Uncontrolled

Household PopulationPlace 2

WEIGHT Controlled PopulationPlace 2

* =Uncontrolled

Household PopulationPlace 4

WEIGHT Controlled PopulationPlace 4

* =Uncontrolled

Household PopulationPlace 3

WEIGHT Controlled PopulationPlace 3

GQPlace 1+

+

+

+

GQPlace 2

GQPlace 3

GQPlace 3

Controlled Population

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Data Needs• Block level Census data– Total population– Household population– Housing units– Occupied housing units

• Map files– Census blocks with linked population and housing data– Outline files of subcounty areas– CAMA housing units by year built

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

The Process• Isolate housing units from other property uses• Add boundaries of sub-county geography from

Census year• Estimate new construction each year using GIS

procedures• Determine persons per housing unit for detailed

areas from latest Census• Calculate estimated household population for

each area using HU*VR*PPH

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

2000 Tabulation Blocks for Subcounty Area

Residential Parcels for Subcounty Area

Reasons for Large Errors

• Small numbers• Quality of the housing unit count• Changing PPH and occupancy rates• Boundary files and parcel data problems• Increases or decreases in group quarter

populations• Areas outside property tax jurisdictions

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Osceola County, Florida

Kissimmee city (59,682)

Alternate balance of county (166,393)

Celebration CDP (7,427)

Census balance of county (173,820)

St. Cloud city (35,183)

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Okaloosa County, Florida

Cinco Bayou town (383)

Crestview city (20,978)

Alternate balance of county (83,062)

Wright CDP (21,697)

Census balance of county (104,759)

Valparaiso city (5036)

Shalimar town (717)

Niceville city (12,749)

Mary Esther city 3,851)

Laurel Hill city (537)

Fort Walton Beach city (19,507)

Destin city (12,305)

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Marion-Sumter Counties, Florida

Belleview city (4,492)

Dunnellon city (1,733)

Alternate balance of county (288,085)

The Villages CDP (51,442)

Lake Panasoffkee CDP (3,551)

Silver Springs Shores CDP (6,539)

Census balance of county(349,617)

Wildwood city (6,709)

Webster city (785)

Coleman city (703)

Center Hill city (988)

Bushnell city (2,418)

Reddick town (506)

Ocala city (56,315)

McIntosh town (452)

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Lewis & Clark County, Montana

Helena city (28,190)

East Helena town (1,984)

Alternate balance of county (7,675)

Census balance of county (33,221)

Helena Valley Northwest CDP (3,482)

Augusta CDP (309)

Helena Valley Northeast CDP (2,995)

Lincoln CDP (1,013)

Helena Valley Southeast CDP (8,227)

Helena Valley Westside CDP (1,637)

Helena Valley West Central CDP (7,883)

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Missoula County, MontanaMissoula city (65,770)

Alternate balance of county (30,517)

Census balance of county (43,904)

Condon CDP (353)

Frenchtown CDP (1,358)

Lolo CDP (4,188)

Seeley Lake CDP (1,815)

Orchard Homes CDP (5,673)

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Columbia Falls city (4,596)

Alternate balance of county (38,774)

Census balance of county (59,546)

Kila CDP (392)

Whitefish city (6,264

Kalispell city (19,530)

Batavia CDP (385)

Bigfork CDP (4,199)

Coram CDP (4,596)

Evergreen CDP (7,600)

Helena Flats CDP (1,043)

Hungry Horse CDP (826)

West Glacier CDP (227)

Somers CDP (1,092)

Martin City CDP (500)Marion CDP (886)

Little Bitterroot Lake CDP (194)

Lakeside CDP (2,492)

Flathead County, Montana

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Gallatin County, MontanaBelgrade city (7,378)

Alternate balance of county (38,774)

Census balance of county (39.997)

Amsterdam/Churchill CDP (1,046)

West Yellowstone town (1,271)

Three Forks city (1,862)

Manhattan town (1,495)

Bozeman city (34,250)

Willow Creek CDP (210)

Ponderosa Pines CDP (336)

Logan CDP (99)

King Arthur Park CDP (7389)

Gallatin Gateway CDP (856)

Four Corners CDP (3,146)

Big Sky CDP (1,876)

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Spokane County, WashingtonAirway Heights city (6,114)

Alternate balance of county (88,764)

Census balance of county (136,108)

Millwood city (1,786) Medical Lake city (5,060) Liberty Lake city (7,591)

Deer Park city (3,652)Cheney city (10,590)

Green Bluff CDP (761) Four Lakes CDP (512)

Fairwood CDP (19,102)

Country Homes CDP (5,841)

Spokane city (208,916) Spangle city (278)

Rockford town (470)

Fairfield town (612) Latah town (183)

Spokane Valley city (89,755) Waverly town (106)

Town and Country CDP (4,857) Otis Orchards-East Farms CDP (6,220)

Mead CDP (7,275)

Fairchild AFB CDP (2,776)

Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Conclusion

• Advantage– Political boundaries are not a hindrance..

• Disadvantage– Quality CAMA/GIS data is not available for many

areas

If good building permit data is unavailable, use of alternate estimates of housing units may be warranted.Pacific Northwest Regional Economic Conference Spokane WA May 16, 2013

Bureau of Business and Economic ResearchThe University of Montana-Missoula

Missoula MT 59812243-5113

243-2086 (FAX)Jim.Sylvester@business.umt.edu

Jim Sylvester