Physician supply in Ontario: further observations on SHARP and the SHARP projections.

In this issue (see pages 1395 to 1398) Eva Ryten questions the validity of the data that supported the projection of a surplus of physicians in Ontario over the next two decades, as presented in an earlier article in CMAJ by Denton, Gafni and Spencer. The authors maintain that the data they used were appropriate. Although the average annual growth rate for the early 1990s calculated from Ontario Health Insurance Plan (OHIP) billing data is somewhat lower than the rate they projected for the decade as a whole, the OHIP-based rate is much closer to their figure than Ryten's rate. They also disagree with Ryten in their belief that the recent reduction of medical school enrollment will have a negligible effect on the physician population by the year 2000. They argue too that Ryten misunderstands the nature of the imbalance they project between the availability of intern and resident services and the requirements for those services. Finally, the authors note that there is an argument for setting requirements for practising physicians at levels lower than they had assumed. For that reason, even if the supply of practising physicians were to grow less rapidly than projected, a substantial surplus could still result by the year 2000.