California Health Interview Survey


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 Hundreds of health statistics

CHIS interviews Californians on hundreds of health topics, including health status, gender identity, substance use and more. For example, 2018 CHIS estimates more than 1 in 4 California adults who use pot said their doctor or health care provider recommended its use.
Learn more about our sample and the questions we ask.

Sample Design


The California Health Interview Survey (CHIS) is a telephone survey that uses a dual-frame random-digit-dial (RDD) technique. By using traditional landline RDD and cell-phone RDD sampling frames, it is representative of the state's population. A supplemental surname list frame is used to ensure representation of the Korean and Vietnamese households. 

Given changes in the telephone survey landscape in recent years, CHIS is transitioning to a new sample design beginning in 2019. You can read more about the new methods here.

Geographic groups

CHIS data can be analyzed at the county level for the state's 41 most populated counties. The remaining 17 counties are combined into three different groups. See sample design summaries below. 

Age groups

CHIS asks questions that are shared across age groups and also some questions that are unique to only one age group: children (0-11 years of age), adolescents (12-17 years of age), and adults (18 years and older).

Race/ethnicity groups

With a large sample of a diverse population, CHIS data have great ability to report on racial/ethnic differences.

CHIS 2017-2018

CHIS 2015-2016

CHIS 2013-2014

CHIS 2011-2012

CHIS 2009

CHIS 2007

CHIS 2005

CHIS 2003

CHIS 2001