1. Dr. Simon, Ms. Operskalski, Dr. Stewart, and Dr. Carrell are with the Group Health Research Institute, Group Health Cooperative, Seattle (e-mail: ). Dr. Coleman is with the Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena. Dr. Yarborough and Dr. Lynch are with the Center for Health Research, Kaiser Permanente, Portland, Oregon. When this work was done, Ms. Hunkeler, who is now retired, was with the Division of Research, Kaiser Permanente, Oakland, California. Dr....