A multiple regression analysis was undertaken of variables identified in the literature as underlying the relationship between community characteristics and the availability and use of home health services. The literature on social science and health care administration was reviewed to identify the variables that theoretically underlie different rates of home health care use among communities. County statistics then were used to quantify many of those variables that, when considered in combination, should explain much of the use of home health services. Three categories of variables--general community characteristics, health sector characteristics, and service availability--contribute roughly equal amounts to the total explained variance of 25 percent. Viewed from the opposite perspective, 75 percent of the use of Medicare home health benefits remains unexplained despite the purported strong association between the variables employed in this analysis and the use of home health services. These findings abase the long-held belief that substitution of inpatient services for home care is commonplace, and they suggest the potential effectiveness of community-level strategies to promote the use of home health services, particularly efforts to increase their availability.