The use of clinical evidence and cost information in coverage and medical necessity decision-making within managed care organizations is not well understood. This national study of medical directors of managed care plans provides information about how plans use evidence and cost to make decisions about the coverage of new health interventions. Most consider evidence of clinical effectiveness paramount in making such decisions; cost information plays a varied, but substantially secondary, role. Introduction of new technologies may be more dependent on high-quality evidence of effectiveness than professional consensus and less formal sources of evidence. Stakeholder interest in mandatory solutions remains controversial.
