Categorizing and evaluating corporate plans for managed care was the goal of this study conducted by the University of North Carolina, Chapel Hill. This study examined the managed care programs of 50 of the Fortune 500 firms to determine the effect of managed care on employees' use of care and on health care costs. The investigators planned to develop a typology of managed care with respect to the scope of "managed care" initiatives and the rigor with which they are pursued. The typology was then to be used to test whether managed care reduces the level and rate of increase of costs at the firm and worksite levels. However, significant data problems reduced the accuracy and utility of the typology, such that it could not be applied to accomplish the goals of the project.