The study developed a model for projecting potential economies from manpower substitution among the four core mental health professions and applied the model to a proposed substitution situation which would substitute psychologists for psychiatrists in the delivery of a proportion of present private practice (fee-for-service) psychiatry services in British Columbia. The model identifies three controlling variables: treatment substitutability (TS), practice privilege constraints (PPC), and relative payment rates (RR). In the model, TS and PPC are conceptualized as determining the estimated substitutable share of costs (SSC%); RR, in combination with the values derived for SSC%, is then used to estimate potential cost savings (CS%). Two conditions were defined for each of the three controlling variables in order to provide a range of possible values for SSC% and CS%. For reasons of data availability, data were obtained from the Manitoba Health Services Commission for private practice psychiatry services for FY 1984 and estimates of SSC% calculated. These estimates were then applied to B.C. Medical Services Commission data for FY 1984, and projected values of CS% calculated. Calculations were made both for all services and for the subset of psychotherapy services, which accounted for 80 percent of the larger set of services. The results of the study indicated considerable possibilities for manpower substitution, ranging from 35 to 70 percent for all services and 40 to 75 percent for psychotherapy services. However, the study also found that while salaried psychologists offered the possibility of substantial cost savings, a fee-for-service arrangement suggested virtually no potential savings. Projected values of CS% for the salaried alternative were 20 to 40 percent for all services and 15 to 30 percent for psychotherapy services but in the fee-for-service alternative, only 4 to 8 percent for all services and 4 to 7 percent for psychotherapy services. Licensure and market rigidities which might pose barriers to implementation were evaluated and a review of professional training standards (TS), licensure standards (PPC), and funding alternatives (RR) indicated that the projected economies could be achieved with no necessity for modifications in existing arrangements. PPC appear to present almost no barriers to economies from the proposed manpower substitution and those barriers which are presented by TS and RR limitations still allow considerable potential for economies. Thus, the greatest opportunities for intervention in achieving and enhancing the projected, economies appear to be in the exploration of relative payment rates and relative effectiveness of treatment methods (e.g., psychotherapy vs. pharmacotherapy). The study concludes with a discussion of factors lying outside the boundaries of the model but which impinge, nonetheless, upon the feasibility of the proposed substitution and fall, necessarily, to policy makers to address. The existing network of B.C. community mental health centres was suggested as a possible mechanism for the delivery of the substitutable share of private practice psychiatry services. / Medicine, Faculty of / Population and Public Health (SPPH), School of / Graduate