BACKGROUND: Cluster randomized trials (CRTs) offer unique advantages over standard randomized controlled clinical trials (RCTs) and observational methodologies, and may provide a cost-efficient alternative for answering questions about the best treatments for common conditions.

OBJECTIVES: To describe health plan leaders' views on CRTs, identify barriers to conducting CRTs, and solicit recommendations for increasing the acceptability of CRTs.

RESEARCH DESIGN: Qualitative in-depth telephone interviews with leaders from 8 health plans.

SUBJECTS:: Thirty-four health plan leaders (medical directors, pharmacy directors, Institutional Review Board leaders, ethics leaders, compliance leaders, and others).

MEASURES: Qualitative analysis of interview transcripts to identify barriers, factors influencing leaders' views, ethical issues, aspects of CRTs that appeal to leaders, and recommendations for increasing acceptability of CRTs.

RESULTS: Multiple barriers were identified, including financial costs, concerns about stakeholders' perceptions of CRTs, impact on physicians' prescribing habits, and formulary changes. Most leaders recognized the potential value of studying the comparative effectiveness of therapeutics, and many stressed the need for head-to-head trials. Leaders' views would be influenced by variations in study design and implementation. Recommendations for increasing acceptability of CRTs included ensuring that the fiscal impact of a CRT be budget neutral, and that researchers educate stakeholders and decision-makers about CRTs.

CONCLUSIONS: Overall, health plan leaders recognized the need for studies of the comparative effectiveness of therapeutics under real world conditions, and many expressed support for CRTs. However, researchers seeking to conduct CRTs in health plans are likely to face numerous barriers, and preparatory work will be essential.