Department of Finance
915 L Street
Sacramento, CA 95814

E-1 Population Estimates for Cities, Counties, and the State — January 1, 2011 and 2012

May 2012

• E-1 2012 Press Release  (.pdf <1MB)
• E-1 Cities, Counties, and the State Population Estimates with Annual Percent Change— January 1, 2011 and 2012 (.xls, multi-sheet, <1MB)
• Tables of January 2012 City Population Ranked by Size, Numeric and Percent Change (.xls, multi-sheet, <1MB)

Contents

This report provides revised population estimates for January 1, 2011 and provisional population estimates for January 1, 2012 for the state, counties and cities, and a calculation of annual percent change. These population estimates incorporate 2010 census counts.

Methodology

Introduction.  The January state, county, and city populations are independently estimated using change models benchmarked to federal census counts from the 2010 Summary  File 1. The state population estimate is produced using the Driver License Address Change (DLAC) method. County population estimates result from the average of three separate methods, as described below. The final distribution of county proportions is adjusted to the independently estimated state total to derive the county estimates. City estimates are produced using the Housing Unit Method (HUM) detailed below, and are then raked to be consistent with the state and county estimates. Through the raking process, city and unincorporated area estimates are aligned with the more robust state and county estimating models that employ multiple data sets available only at the higher geographic levels.

City and Unincorporated Area Estimates. The HUM estimates total and occupied housing units, household size, household population, and group quarters population. Housing units are estimated by adding new construction and annexations and subtracting demolitions and conversions starting from the 2010 benchmark or based on the prior year’s estimate. Housing unit changes are supplied by local jurisdictions and the U.S. Census Bureau. All 539 reporting jurisdictions complied with Finance’s survey request this year. Occupied housing units are estimated by applying a derived civilian vacancy rate, based on 2010 benchmark data, to the estimated civilian housing units. Adjustments to the census vacancy rates are made periodically; however, exact data on foreclosures or other housing market indicatorswere not available to adjust vacancy rates.  Military occupied housing units are added to civilian occupied housing units to calculate total occupied housing units. Military surveys are used to track military changes including base realignments and closures. The household population estimate is derived by multiplying the number of occupied housing units by the current persons per household. The persons per household estimates are based on 2010 benchmark data and are updated by incorporating the current county population series into these estimates. The group quarters population has been updated using the Census Bureau’s 2010 SF1 File and reported changes for group quarters by state, federal, and local agencies. The household and group quarters populations are summed to produce the initial city population estimates. These estimates are aligned to the county estimates described below.

County Estimates. County population proportions result from averaging three methods:

Driver License Address Change Method. A modified version of the state DLAC method is used for counties. County proportions of the state total result from changes in county population values for births, deaths, school enrollment, foreign and domestic migration, the number of driver licenses by age group, medical care enrollment data for the population 65 and over, and group quarters population.

Ratio-Correlation Method.  This method models change in household population as a function of changes in the distributions of driver licenses, public elementary school enrollments, and housing units. Estimates of county group quarters are added.

Tax Return Method.  County proportions are derived by the U.S. Census Bureau using matched federal income tax returns to estimate inter-county migration along with vital statistics, group quarters, and other information for the population aged 65 and over.

State Estimate. The state population is estimated using the DLAC method. This composite method separately estimates the population under age 18, 18 through 64, and 65 years and older. Administrative records such as births, deaths, driver license address changes, the number of driver licenses by age group, tax return data, medical care enrollment data for the population 65 and over, immigration, public elementary school enrollments, and group quarters population are among the data used in this method. All data are in summary tables and do not reveal the identity of any individual.

Data Considerations

Sources. Data used in estimation models come from administrative records of several state and federal government departments and agencies, and from the local jurisdictions for which Finance produces population estimates. Because timeliness and coverage in these series vary, corrections, smoothing, and other adjustments may be applied. Changes to 2010 Summary File 1 data in the classification of student housing on or near campus was necessary to remain consistent with the census group quarters definition. In only a few instances, some student housing (residence hall and apartment units) counted as household population in the census was redefined as group quarter student housing population. College dorm group quarter population is defined as student population living in residence halls and apartment units located on or near college campuses.

Acknowledgments

The E-1 Report was prepared by city estimates staff: Daniel Sheya, Doug Kuczynski, and Alex Alvarado. State and county estimates were prepared by Linda Gage. Technical and analytical expertise was provided by Evaon Schnagl and Walter Schwarm. Lynne Barile provided administrative assistance. Nancy Gemignani provided website assistance. This report was produced under the general direction of Bill Schooling, Chief, John Malson, Assistant Chief, and Judi McClellan, Research Manager II.

Suggested Citation

State of California, Department of Finance, E-1 Population Estimates for Cities, Counties, and the State with Annual Percent Change — January 1, 2011 and 2012. Sacramento, California, May 2012.

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