Effects of Survey Mode, Patient Mix, and Nonresponse on CAHPS® Hospital Survey Scores

To evaluate the need for survey mode adjustments to hospital care evaluations by discharged inpatients and develop the appropriate adjustments. A total of 7,555 respondents from a 2006 national random sample of 45 hospitals who completed the CAHPS((R)) Hospital (HCAHPS [Hospital Consumer Assessments of Healthcare Providers and Systems]) Survey. We estimated mode effects in linear models that predicted each HCAHPS outcome from hospital-fixed effects and patient-mix adjustors. Patients randomized to the telephone and active interactive voice response (IVR) modes provided more positive evaluations than patients randomized to mail and mixed (mail with telephone follow-up) modes, with some effects equivalent to more than 30 percentile points in hospital rankings. Mode effects are consistent across hospitals and are generally larger than total patient-mix effects. Patient-mix adjustment accounts for any nonresponse bias that could have been addressed through weighting. Valid comparisons of hospital performance require that reported hospital scores be adjusted for survey mode and patient mix.