The application of ACGs in Canada is feasible using existing data. The ability of the ACG system to explain variation in costs is similar to that found in US health systems. While application of ACGs in Canada shows promise, further research is required to examine how closely they reflect population morbidity burdens and health care needs.

Objectives: To demonstrate the feasibility of a population-based measure of physician services utilization by type of service as a tool for physician workforce planning. Setting: The Northern Health Region of British Columbia. Design: Retrospective descriptive statistics are compiled about the regional population' s physician services utilization by the specialty of the service, irrespective of the specialty or location of the provider. These are compared to norms based on provincial average utilization, adjusted for age and sex, and norms based on population-to-physician ratio recommendations. Metrics: By specialty type of service: actual utilization; age-sex expected utilization; in-region, out-of-region and out-of-province utilization; full-time equivalency (FTE) values of actual and expected utilization; and FTE requirement to meet a set of recommended population-to-physician targets. Specialty substitution by general practitioners (GPs) is also quantified. Results: The overall estimated deficit in physician numbers is similar between the two methods (51 versus 54), but the magnitude of surplus or deficit by specialty is greater with the population-to-physician method. Conclusion:The method targets an equitable distribution, rather than normative ideal physician supply. The magnitude of estimated surplus or deficit at the level of each specialty is greater with the population-to-physician ratio approach. The latter fails to consider interregional flow and specialty substitution. A population-based utilization approach is demonstrated to be a feasible, and in many ways superior, tool for physician resource planning. RésuméObjectifs : Démontrer la faisabilité d'une mesure -fondée sur la population -de l'utilisation des services des médecins par type de service comme outil pour la planification de la main-d' oeuvre médicale. Cadre : Région sanitaire du Nord de la Colombie-Britannique. Conception : Des statistiques descriptives rétrospectives sont compilées au sujet de l'utilisation des services des médecins par la population régionale, par la spécialité du service, sans égard à la spécialité du fournisseur ou à son emplacement. Ces statistiques sont comparées aux normes fondées sur l'utilisation provinciale moyenne, ajustées en fonction de l' âge et du sexe, et à des normes fondées sur les recommandations concern-

This article reviews the Adjusted Clinical Group Case-Mix System and describes how it is being applied in the management of physician services in British Columbia. Developed in the United States for management and research, adjusted clinical groups are used to measure the illness burden and health service needs of individuals and, when aggregated, of populations, by grouping the range of conditions coded on physician claims and hospital care records over a defined time period, typically one year. In Canadian and United States settings, adjusted clinical groups are up to five times more predictive of ambulatory resource use than are age and sex groups alone. The article describes how adjusted clinical groups are being applied to adjust capitation payments for physician groups in British Columbia's Primary Care Demonstration Project and profiles of physician practice activity.

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