Predicting the work of evaluation and management services.

Physicians, carefully adhering to the definitions of Physicians' Current Procedural Terminology (CPT) billing codes, used the same CPT codes to denote evaluation and management services that varied widely in work and used different codes for services whose work was the same. As payment shifted to the Medicare Fee Schedule, it was important that the coding system be redefined so that codes consistently reflect the resource costs of these services. Redefining these codes for a resource-based payment system required an understanding of how verifiable predictors relate to physician work. Using data obtained from the Resource-Based Relative Value Scale (RBRVS) study regarding 377 services surveyed among physicians in 31 specialties, multiple regression analyses of the relationship of different variables to the mean values of work were performed. Intraservice time, which accounted for 90% of the variance, was the most important predictor of intraservice work. Specification of time, which previously had not been an element in the definitions of CPT codes for evaluation and management services, was useful in refining these codes so that their value corresponds more closely to resource costs. Other predictors of work were site of service or visit type, patient status (new/initial, established/ subsequent), and referral status (consultation, nonconsultation).