Bigger Cell Phone Sample
In 2009, CHIS expanded its cell phone sample to include those who "mainly" use cell phones and those who "only" use mobile telephones. Children and teens interviews were added to the cell-phone sample as well.
CHIS Data Quality
The California Health Interview Survey (CHIS) provides high quality data that accurately represents the California population living in households. CHIS data are well-documented and easy to access and use. Since fielding our first statewide survey of California in 2001, these objectives have guided the evolving survey methods implemented in CHIS.
Like all surveys, CHIS is challenged by a rapidly changing survey environment. Response rates have been declining for the past several decades and the recent growth of cellular telephones introduces potential coverage problems for traditional random digit dial (RDD) sampling methods. Declining response rates may increase the potential for nonresponse bias in CHIS estimates, and the growth of cellular telephones may increase the potential for noncoverage bias in CHIS estimates.
CHIS is at the forefront of efforts to scientifically understand and address potential nonresponse and noncoverage bias. Below are some completed and in-progress studies that we are doing to assess methodological issues related to CHIS and to guide our efforts to maintain the highest standards for data quality. While no single study can definitively demonstrate data quality, taken as a whole the multiple studies conducted to assess CHIS data quality consistently point in the same direction: CHIS data are high quality and accurately represent California's household population.
- CHIS 2007 cell-phone only sample to assess and address noncoverage bias - click for more information
- CHIS 2007 area probability sample in Los Angeles County to assess nonresponse bias - click for more information
- CHIS 2005 neighborhood response propensity study to assess nonresponse, funded by the National Science Foundation - click for more information
- CHIS 2003 benchmarking of key estimates with those from major federal health surveys to assess effects of different survey methods and response rates - click for more information
- CHIS 2003 comparison of CHIS Medi-Cal estimates with other data sources to assess effects of different survey methods and data sources - click for more information
- CHIS methods to maximize response rates and inclusiveness to assure that CHIS data represent California's diverse population - click for more information
- Partial bibliography (PDF) of nonresponse and noncoverage studies (last updated 12-15-08)
