Objective: To evaluate a computerized scheduling model that employs nonlinear optimization to recommend optimal follow-up intervals for patients taking warfarin.; ; Design: Randomized trial.Setting: 5 anticoagulation clinics.; ; Patients/participants: 620 patients expected to receive warfarin for ?6 weeks.; ; Interventions: Computer-generated recommendations for scheduling the next visit were presented to or withheld from practitioners.; ; Measurements and main results: The main outcome measures were the follow-up interval scheduled by the provider,