0092-2102/02/3202/0063$05.00 1526-551X electronic ISSN Interfaces,  2002 INFORMS Vol. 32, No. 2, March–April 2002, pp. 63–73 Mount Sinai Hospital Uses Integer Programming to Allocate Operating Room Time John T. Blake • Joan Donald Department of Industrial Engineering, Dalhousie University, Halifax, Nova Scotia, Canada B3J 2X4 Management Consultant, Riverview, New Brunswick, Canada E1B 1T4 john.blake@dal.ca • jdonald@nbet.nb.ca An integer-programming model and a post-solution heuristic allocates operating room time to the five surgical divisions at Toronto’s Mount Sinai Hospital. The hospital has used this approach for several years and credits it with both administrative savings and the ability to produce quickly an equitable master surgical schedule. (Health care: hospitals. Programming: integer, applications) I n most developed countries, except the United States, strategies for providing universal access to health care while containing costs involve formal or informal caps on health-care spending (Pierskalla and Brailer 1994, p. 470). As a result of centrally con- strained funds, resource-allocation problems in which a central authority must plan for and allocate limited resources to competing groups or services are common issues in health-care planning at the national, regional, and institutional levels. Canadian experience suggests that a centrally im- posed limit on expenditures is an effective method for controlling the size of a national health-care system. While the percentage of gross domestic product (GDP) spentonhealthcareinCanadain1997was9.0percent, the proportion of GDP spent on health care in the United States was 13.6 per cent (Canadian Institute for Health Information 1999, p. 26). Centrally limited bud- gets do, however, create a problem of scarcity. Under such systems, demand for resources outstrips supply, necessitating a complex and often contentious process for determining how to best allocate resources between competing demands. In a resource-allocation problem at Mount Sinai This paper was refereed. Hospital, the hospital must allocate a limited amount of operating room (OR) time to its surgical divisions. After a decrease in provincial funding resulted in a reduction in the total amount of operating-room time available, we devised a method for equitably dividing operating-room time using integer-programming. Other authors have employed a similar approach to problems in the public sector. For example, Keown and Martin (1976) describe the application of integer goal programming to capital-budgeting decisions in hos- pitals; Tingley and Liebman (1984) present an integer- programming model that allocates federal funds for social welfare programs to local provider organiza- tions; and Diminnie and Kwak (1986) and Kwak and Diminnie (1987) describe the use of integer goal pro- gramming to select program alternatives under a shrinking budget in a university environment. Background As in the United States, health care in Canada is deliv- ered by independent physician-entrepreneurs, who are paid a fixed fee for each service they provide. Hos- pitals in Canada are private, not-for-profit corpora- tions. Neither physicians nor hospitals are formally tied to the federal or provincial governments. Each