​Summary: The decline of telephone surveys due to low response rates and cultural shifts in telephone use motivated the UCLA Center for Health Policy Research to consider a methodological redesign for the California Health Interview Survey (CHIS) in order to implement more cost-effective methods. The redesign process included working with consultants and conducting two field experiments. The resulting design for CHIS 2019 production is a mixed-mode survey, using an address-based sampling (ABS) frame with a mail push-to-web survey followed by a telephone nonresponse follow-up. The primary purpose of this report is to evaluate how the methodological changes impact trending data across cycles. Statewide pilot data from 2018 is used as a reference point related to the redesign.

There are three primary reasons for shifts in trends for CHIS 2019:

1) Sample compositional changes due to sampling frame and mode

2) Measurement changes related to mode

3) Actual changes in the population over time

Findings: ​Based on the evaluations conducted, CHIS feels assured that data users will be able to trend most substantive variables, but we encourage data users to interpret trends with caution. While this report cannot examine every trend for every variable, it should provide sufficient background and clear examples to help researchers interpret trends and make decisions about whether trending CHIS data across this methodological redesign is appropriate.​

Read the Publication:

• Research Report: CHIS 2019-2020 Redesign: Rationale, Empirical Evaluation, and Trends