28. ICF, Inc., Final Report (see note 7 above).
29. Memorandum from Lewin/ICF, Inc. and Group Health Association of America to Chris Bladen, Division of Health Financing Policy, U.S. Department of Health and Human Services, Washington, DC, June 24, 1988.
30. For a review of early research studies on utilization rates in HMO and fee-for-service settings and across HMOs, see Luft, Harold S., Health Maintenance Organizations: Dimensions of HMO Performance, New York: Wiley, 1981.
31. See, for example, Yelin, Edward H., Henke, Curtis J., Kramer, Jane S., Nevitt, Michael C., Shearn, Martin, and Epstein, Wallace V., "A Comparison of the Treatment of Rheumatoid Arthritis in Health Maintenance Organizations and Fee-for-Service Practices," New England Journal of Medicine, Vol. 312, April 11, 1985, pp. 962-967. Also see Quick, Jonathan D., Greenlick, Merwyn R., and Roghmann, Klaus J., "Prenatal Care and Pregnancy Outcome in an HMO and General Population: A Multivariate Cohort Analysis," American Journal of Public Health, Vol. 71, April 1981, pp. 381-390.
32. For a study that assumed that the differential use of diagnostic testing was due to its increased profitability to fee-for-service providers, see Epstein, Arnold M., Begg, Colin B., and McNeil, Barbara J., "The Use of Ambulatory Testing in Prepaid and Fee-for-Service Group Practices: Relation to Perceived Profitability," New England Journal of Medicine, Vol. 314, April 24, 1986, pp. 1089-1094.
33. Scovern, Henry, "Hired Help: A Physician's Experiences in a For-Profit Staff-Model HMO," New England Journal of Medicine, Vol. 319, September 22, 1988, pp. 787-790.
34. For an example of a discussion on referral patterns, see Piland, Neil E, White, Robert E., and Smith, Howard L., "Physician Referral Patterns: Implications for Group Practice," GHAA Journal, Vol. 7, Winter 1986, pp. 4-12. For an example of a discussion on provider feedback, see Berwick, Donald M., and Coltin, Kathryn L., "Feedback Reduces Test Use in a Health Maintenance Organization," Journal of the American Medical Association, Vol. 255, March 21, 1986, pp. 1450-1454. See also Braham, Robert L, and Ruchlin, Hirsch S., "Physician Practice Profiles: A Case Study of the Use of Audit and Feedback in an Ambulatory Care Group Practice,'' Health Care Management Review, Vol. 12, 1987, pp. 11-16.