Patterns of surgical and nonsurgical hospital use in Michigan communities from 1980 through 1984.

Hospital discharge rates vary substantially among 60 communities in Michigan. (R2 = 90 percent and R2 = 85 percent of the systematic variance is explained by community effects for nonsurgical and surgical discharges, respectively.) The ranking of communities by discharge rates is stable over a five-year period (Spearman rho = 0.78 for nonsurgical discharges and 0.72 for surgical discharges). Surgical discharge rates decreased substantially (4 percent per year) over this time period, while nonsurgical rates showed no consistent pattern. Communities with exceptional discharge rates showed no substantial or significant regression toward the mean through the five-year study.