Managed care plans' growing interest in practice guidelines is driven by their need to control costs, ensure consistency of care, and demonstrate improved performance. By using practice guidelines, plans are making a conscious decision about the care they intend to provide, reflecting the trade-off between costs and benefits. When published guidelines differ from a plan's clinical and financial objectives, they are typically customized with the active participation of the network physicians. Since published guidelines can be inconsistent, outdated, or too complex, local adaptation may be useful. Yet some changes may compromise the quality of patient care
