PERFORMANCE COMPARISON IN GERIATRIC-MEDICINE - A STUDY IN ONE DEPARTMENT

It is now commonplace to base performance comparison on productivity m easurements. Yates recommended the use of Barber-Johnson diagrams to c ompare activity in acute specialties, but he did not commend their use in specialties with large numbers of beds and long lengths of stay. P erformance comparison in geriatric medicine is difficult because facto rs such as the case mix and the discharge destination influence throug hput. We used two mathematical models to compare the performance of fi ve consultants in the same department. A Monte Carlo simulation based on historic-frequency tables indicated that the mean annual admissions to forty beds by the five consultants would vary between 592 and 748 admissions per year and a two-sample t-test indicated that only two of the consultants were the same, whereas the two-compartment flow model based on the average bed occupancy predicted the annual admissions to be between 650 and 856 and it indicated that the two consultants trea ted longer-stay patients differently. Thus the models identified diffe rences in consultant performance which were not shown by simple statis tics. The information required to decide if the variation in consultan t performance is due to clinical or other differences is not yet routi nely available. However, the benefit of modelling is that it identifie s areas of variation and facilitates exploratory discussion.