Zones

On this website, data are shown by cancer reporting zone. These zones have been designed so that they have a minimum population, have similar demographic and socioeconomic characteristics, and are geographically compact (they minimize the distance between different parts of the zone). The minimum population for each zone is 50,000 people.

Counties with larger populations (more than 100,000 people) were divided into multiple zones by combining adjacent census tracts. For the rest of the state, adjacent counties and parts of counties were combined to form zones. Three demographic and socioeconomic characteristics were used to determine similarity: the percent of the population who are not non-Hispanic White, percent of the population with incomes below poverty, and the proportion of the population living in urban and rural areas.

We used population data from Census 2010 and Census 2010 tract geographies to construct the zones. Poverty data came from the American Community Survey 2012-2016 5-year data. We used a software zone design program called AZTool to identify aggregations of adjacent tracts and counties that optimize the three objectives: a target population of 50,000, geographic compactness, and similarity in terms of minority population, poverty, and urbanicity characteristics.

Medical Service Study Areas (MSSAs)

As defined by California's Office of Statewide Health Planning and Development (OSHPD) in 2013, "MSSAs are sub-city and sub-county geographical units used to organize and display population, demographic and physician data." Each census tract in CA is assigned to a given MSSA. The most recent MSSA dataset (2014) was used. Spatial data are available via OSHPD at the California Open Data Portal.

Census Places

Census places are bounded areas designating cities, towns, unincorporated populations, and other "settled concentrations of populations" (more information at the Census website). As detailed population denominators for Census 2020 geographies are not yet available, updated incidence rates for Census places cannot be generated. An archived version of California Health Maps including Census places can be found at archive.californiahealthmaps.org.

Congressional Districts

Congressional districts define the boundaries around areas which are represented by the U.S. House of Representatives (more information at the Census website). As detailed population denominators for Census 2020 geographies are not yet available, updated incidence rates for Congressional districts cannot be generated. An archived version of California Health Maps including Congressional districts can be found at archive.californiahealthmaps.org.

State Senate Districts

California State Senate districts define the boundaries of areas represented in the CA state senate (more information at the Census website). As detailed population denominators for Census 2020 geographies are not yet available, updated incidence rates for State Senate districts cannot be generated. An archived version of California Health Maps including State Senate districts can be found at archive.californiahealthmaps.org.

State Assembly Districts

California State Assembly districts define the boundaries of areas represented in the CA state assembly (more information at the Census website). As detailed population denominators for Census 2020 geographies are not yet available, updated incidence rates for State Assembly districts cannot be generated. An archived version of California Health Maps including State Assembly districts can be found at archive.californiahealthmaps.org.

Counties

California Counties define the boundaries of the 58 California Counties. Spatial data are available from NHGIS (IPUMS NHGIS, University of Minnesota, www.nhgis.org).

Cancer incidence rates

Incidence rates for zones and MSSAs were calculated using case counts from the California Cancer Registry. Population data from SEER census tract estimates by race/origin, Vintage 2020, were used to estimate population denominators. State and county rates were computed based on data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program, to take advantage of annual population data from the National Center for Health Statistics. Cancer case numerator data in SEER are equivalent to cancer case numerator data from the California Cancer Registry.

Age-Adjusted Incidence Rate (AAIR): Age-adjustment is a statistical method that allows comparisons of incidence rates to be made between populations with different age distributions. This is important since the incidence of most cancers increases with age. An age-adjusted cancer incidence (or death) rate is defined as the number of new cancers (or deaths) per 100,000 population that would occur in a certain period of time if that population had a 'standard' age distribution. In the California Health Maps, incidence rates are age-adjusted using the U.S. 2000 Standard Population.

Aggregation: Collections of smaller units grouped together for the purposes of statistical reporting. See Methodology for more information.

Annual Checkups: Visits to doctor for routine checkup within the past year among adults aged 18+ years.
Source: PLACES Project. Centers for Disease Control and Prevention, 2023.

Cervical Cancer Screening: Cervical cancer screening among adult women aged 21-65 years.
Source: PLACES Project. Centers for Disease Control and Prevention, 2023.

Colorectal Cancer Screening: Colorectal cancer screening among adults aged 50-75 years.
Source: PLACES Project. Centers for Disease Control and Prevention, 2023.

Confidence Interval: A statistical measure of the precision of the observed incidence rate. The lower confidence interval (LCI) and upper confidence interval (UCI) provide a range within which the true rate is thought to be with 95% confidence. Rates based on larger numbers are subject to less variation.

Data Suppression: According to California Department of Public Health guidelines, cancer incidence rates cannot be reported if based on fewer than 15 cancer cases and/or 10,000 population counts. Incidence rates with fewer than 15 cases and/or 10,000 population-at-risk for a given cancer site/sex/racial or ethnic group are not shown to ensure confidentiality and stable statistical rates.

Demographics: Statistical data relating to the population and particular groups within it.

Foreign Born: Percent of residents who were born outside the United States.
Source: American Community Survey, 2015-2019 and 2018-2022.

Incidence: The number of new cases of cancer diagnosed over a specified period of time (per population).

Mammograms: Mammography use among women aged 50-74 years.
Source: PLACES Project. Centers for Disease Control and Prevention, 2023.

Obesity: Obesity among adults aged 18+ years.
Source: PLACES Project. Centers for Disease Control and Prevention, 2023.

Over 65: Percent of residents age 65 years and older.
Source: SEER census tract estimates by race/origin, Vintage 2020.

Population: Total population, based on SEER census tract estimates.
Source: SEER census tract estimates by race/origin, Vintage 2020. Note: state and county cancer incidence rates are calculated using population data from the National Center for Health Statistics to match published rates.

Preventive Care (Men, 65+ years) Older adult men aged 65 years or older who are up to date on a core set of clinical preventive services: Flu shot past year, Pneumococcal vaccination (PPV) shot ever, Colorectal cancer screening.
Source: PLACES Project. Centers for Disease Control and Prevention, 2023.

Preventive Care (Women, 65+ years) Older adult women aged 65 years or older who are up to date on a core set of clinical preventive services: Flu shot past year, Pneumococcal vaccination (PPV) shot ever, Colorectal cancer screening, and Mammogram past 2 years.
Source: PLACES Project. Centers for Disease Control and Prevention, 2023.

Race and Ethnicity: Race and ethnicity is categorized as: Non-Hispanic (NH) White, NH Black, NH Asian/Pacific Islander, or Hispanic. "All races and ethnicities" includes all of the above, as well as other and unknown race or ethnicity and American Indian/Alaska Native. The latter two groups are not reported separately due to small numbers for many cancer sites.

Racial and Ethnic Composition: Distribution of residents' race and ethnicity (e.g., % Hispanic, % non-Hispanic White, % non-Hispanic Black, % non-Hispanic Asian/Pacific Islander).
Source: SEER census tract estimates by race/origin, Vintage 2020.

Rural: Percent of residents who reside in blocks that are designated as rural.
Source: US Census, 2010 and 2020.

Sex: California Cancer Registry defines this field as the sex or gender of the cancer patient, and codes available are male, female, intersex, transsexual, and transgender (natal male, natal female, or not specified). However, categories beyond male and female are not consistently coded by medical reporting facilities, and population estimates for gender categories beyond male and female are not available. Thus, cancer incidence data are reported for only male and female sex at this time.
Source: PLACES Project. Centers for Disease Control and Prevention, 2023.

Smoking: Current smoking among adults aged 18+ years.
Source: PLACES Project. Centers for Disease Control and Prevention, 2023.

Socioeconomic Status (Neighborhood Level): A composite measure of seven indicator variables created by principal component analysis; indicators include: education, blue collar job, unemployment, household income, poverty, rent, and house value. Quintiles based on state distribution, with quintile 1 being the lowest SES and 5 being the highest.
Source: American Community Survey, 2015-2019 and 2018-2022.

Uninsured: Percent of residents who did not have health insurance.
Source: American Community Survey, 2015-2019 and 2018-2022.