Evaluating the effect of translation on Spanish speakers' ratings of Medicare
This study examined the equivalence of the English and Spanish versions of the Medicare Consumer Assessment of Health Care Study (CAHPS®) fee-for-service (FFS) survey among 2,996 Hispanic Medicare beneficiaries. Multigroup confirmatory factor analyses indicated that with few exceptions the factor structures were very similar for the English and Spanish surveys. However, item response theory-based methods for investigating differential item functioning (DIF) revealed that several items demonstrated threshold-related DIF, suggesting that respondents in the two languages utilized the response options for the items differently. The results of this study suggest the need for future qualitative research to understand how respondents comprehend the response options in the two languages.