Anticipating market demand: tracking enrollee satisfaction and health over time

To assess guidelines, set by the National Committee for Quality Assurance, for the Health Plan Employer Data and Information Set (HEDIS) 1999 CAHPS 2.0H Survey (formerly the HEDIS 1999 Consumer Survey) in the light of user's needs to monitor health plan performance over time, monitor sick enrollees, and prioritize determinants (drivers) of enrollee experience.

A two-wave, cross-sectional/longitudinal panel design, consisting of national surveys mailed to employees of three major USA corporations in 1993 and 1995.

Samples included employees selected to represent 23 major managed care and indemnity plans in five regions of the USA. In 1993, 14 587 employees responded and in 1995 9018 employees responded (response rates: 51 and 52%). The longitudinal panel sample included 5729 employees who completed both surveys and stayed in the same plan for both years. STUDY MEASURES: The main 1993 and 1995 surveys consisted of 154 and 116 items, respectively. Panel survey content assessed care delivery, plan administration, functional status, well being, and chronic disease.

CAHPS 2.0H's point-in-time, cross-sectional design was unable to detect selection bias and led to an inaccurate view of change in performance. CAHPS 2.0H's use of aggregate samples masked key differences between healthy and sick enrollees; e.g. the sick became less satisfied over time. The association-based, statistical techniques that many survey users will employ to prioritize the 'drivers' of enrollee experience in the absence of CAHPS 2.0H guidelines yielded a less efficient account of change than the multi-method/multi-trait approach developed for this project.

Consumer experience of plan performance is best understood when the separate contributions of longitudinal membership and movement in and out of plans are clarified, changes in health are identified, changes for sick and healthy enrollees are compared, and plan performance on satisfaction criteria is probed to give confirmation and detail. Changes to the CAHPS 2.0H approach in HEDIS 1999 will facilitate user application of these principles.