Multisite randomized controlled trials in health services research: Scientific challenges and operational issues

Although well-designed randomized controlled trials (RCT) provide the stron gest evidence regarding causation, only relatively recently have they been used by health services researchers to study the organization, delivery, qu ality, and outcomes of care. More recent yet is the extension of multisite RCTs to health services research. Such studies offer numerous methodologica l advantages over single-site trials: (1) enhanced external validity; (2) g reater statistical power when studying conditions with a low incidence br p revalence, small event rate in the outcome (eg, mortality), and/or large va riance in the outcome (eg, health tare costs); and (3) rapid recruitment to provide health care organizations and policy makers with timely results. T his paper begins by outlining the advantages of multisite RCTs over single- site trials. it then discusses both scientific challenges (ie, standardizin g eligibility criteria, defining and standardizing the intervention, defini ng usual care, standardizing the data collection protocol, blinded outcome assessment, data management and analysis, measuring health care costs) and operational issues (ie, site selection, randomization procedures, patient a ccrual, maintaining enthusiasm, oversight) posed by multisite RCTs in healt h services research. Recommendations are offered to health services researc hers interested in conducting such studies.