LOS ANGELES DEPARTMENT of CITY PLANNING
DEMOGRAPHIC RESEARCH UNIT
|A BRIEF SUMMARY of HOUSING UNIT METHODOLOGY|
The Demographic Research Unit calculates population estimates using a
housing unit method in which the change in the number of housing units at
the census tract level is used to distribute the citywide population to
census tract areas.
Housing Units – Total housing units from 1990 Census.
Estimated Residential Construction Units – Building permits are compiled from PCIS data files developed by Department of Building and Safety (DBS). Housing growth calculated from building permits assumes a lag time between the issuance of permits and completion of construction. The lag times provided by Dave Schnitger of DBS (in number of months) are:
One percent of all building permits never result in the actual
construction of a housing unit. Therefore, a factor of .99 is used to
estimate completed new units.
Housing units as of October 1 are calculated in the following mannerfor each year:
HU98 = [(BP91 + BP92 + … + BP98)* .99] + HU90,
HU99 = [(BP91 + BP92 + … + BP99)* .99] + HU90,
HU98 = Estimate of total residential housing units for October 1, 1998;
HU99 = Estimate of total residential housing units for October 1, 1999;
BP91, ..., BP98 = Residential building permits issued in 1990 – 1998 that would result in the completion of a housing unit after April 1, 1990 and prior to the date of the estimate less demolition permits issued during this period;
BP91, ..., BP99 = Residential building permits issued in 1990 – 1999 that would result in the completion of a housing unit after April 1, 1990 and prior to the date of the estimate less demolition permits issued during this period; and,
HU90 = Reported housing units by 1990 Census.
1990 Occupancy Rate - The occupancy rate is calculated by dividing the number of occupied units by the total number of housing units as reported in the 1990 Census.
Occupancy Rate – Residential Electrical Customer data file developed by Department of Water and Power is used to estimate the occupancy rate.
Single Family Housing Units – Include attached and detached single housing units, and mobile homes.
Multiple Family Housing Units – Include condominium, apartment, and other units.
1990 Persons per Household – The household (or resident) population as reported in the 1990 Census divided by the number of occupied housing units.
Household Population – The number of occupied housing units multiplied by the number of persons per household.
Citywide Total Household Population – The sum of sub-area household population estimates within the City.
Published Citywide Total Population – This estimate is obtained from State of California Department of Finance (DOF).
Citywide Rake Factor – The citywide total population estimate divided by the published citywide total population developed by State of California Department of Finance.
School Enrollment – These data are obtained from the Los Angeles Unified School District (LAUSD) and are compiled by the Framework Monitoring Section to Community Planning Areas.
Group Quarter Population – This component is primarily a combination of military personnel living in barracks, college students living in dormitories, and persons residing in institutions. It is calculated by using the ratio of group quarter population and household population on reported 1990 Census for the estimate period.
Citywide Total Population – The sum of the citywide total household population estimate and the group quarter population estimate.