California Health Interview Survey


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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.

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 2013-2014

  • Sample Size by County, Age, and Race/Ethnicity (PDF coming)
    See actual sample numbers by county and by race, for each age group. Sample sizes will be available in Fall 2015.
  • Sample Design Description​ (PDF, 438k)
    Read the design plan for achieving this survey cycle's sampling goals.

CHIS 2011-2012

CHIS 2009

CHIS 2007

CHIS 2005

CHIS 2003

CHIS 2001