The purpose of this study was to compare the effect of 2 feedback strategies on the adherence to congestive heart failure (CHF) guidelines. Thirty-two hospitals in 4 states were randomized to receive either a written feedback intervention (low-intensity intervention [LII]) or an intervention involving feedback, a physician liaison, and quality improvement tools (high-intensity intervention [HII]). CHF quality indicators were assessed, and quality managers were interviewed at baseline and remeasurement. No significant changes in quality indicators were found as a result of either intervention. Seventy-eight percent of quality managers indicated that hospital project implementation had not begun until shortly before remeasurement. HII quality managers perceived the CHF project as significantly more successful compared with LII quality managers (63% versus 13%, P < .01). Evaluation of the effects of external feedback on practice behavior requires sufficient time for organizational and individual clinician change to occur. Physician liaisons may play a role in facilitating this change.