This report provides population estimates for January 1, 2011, through January 1, 2020, for the state, counties, and cities. The population estimates benchmark for April 1, 2010 is also provided.
City and Unincorporated Area Estimates.
The Housing Unit Method (HUM) is used to estimate total and occupied housing units, household size, household population, and group quarters population. American Community Survey (ACS) data were used to distribute 2010 census housing units into our standard housing types (single detached units, single attached units, two to four units, five plus or apartment units, and mobile homes). Housing units are estimated by adding new construction and annexations and subtracting demolitions, and adjusting for units lost or gained by conversions. Annual housing unit change data are supplied by local jurisdictions and the U.S. Census Bureau. Occupied housing units are estimated by applying a derived civilian vacancy rate to the estimated civilian housing units. Vacancy rates are based on 2010 Census benchmark data, adjusted to incorporate the directional changes described by the latest available ACS data. Exact data on foreclosures or other housing market indicators are not reliably available to adjust vacancy rates and are not used.
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. Household population estimates are derived by multiplying the number of occupied housing units by the current persons per household. The persons per household estimates are based on 2010 census benchmark data and are adjusted by raking the current county population series into these estimates. The group quarters population is based on the Census Bureau ’s 2010 SF1 File counts on group quarters and annually adjusted using 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.
The state population is estimated using the Driver License Address Change (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, tax return data, Medicare and Medi-Cal enrollment, immigration reports, elementary school enrollments, and group quarters population are among the data used in this method. All data used to develop these estimates are in summary tables and do not reveal the identity of any individual.
Most of county populations estimates result from averaging the first three methods below. We use a Vital Statistics Method in nine counties (Alpine, Calaveras, Inyo, Mariposa, Modoc, Sierra, Siskiyou, Trinity, and Tuolumne) with populations 65,000 or less.
A modified version of the state Driver License Address Change (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, medical care and medical aid enrollments, and group quarters population.
This method models changes in household population as a function of changes in the distributions of births, driver licenses, school enrollments, labor force, 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.
Vital Statistics Method.
County population estimates result from changes in county population values for births, deaths, and group quarters population.
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 quarters student housing population. College dorm group quarters population is defined as student population living in residence halls and apartment units located on or near college campuses.
State of California, Department of Finance, E-4 Population Estimates for Cities, Counties, and the State, 2011-2020, with 2010 Census Benchmark. Sacramento, California, May 2022.
For questions on the E-4, contact Doug Kuczynski or John Boyne in the Demographic Research Unit at 916-323-4086 or e-mail at email@example.com.