Copyright 1994 by the American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use. American Medical Association, 515 N. State St, Chicago, IL 60610. Volume 271(11) 16 March 1994 pp 872-873 Guidelines You Can Follow and Can Trust: An I deal and an Example [Editorial] McDonald, Clement J. MD; Overhage, J. Marc MD, PhD From the Department of Medicine, Indiana University School of Medicine and the Regenstrief Institute for Health Care, Indianapolis. Editorials represent the opinions of the authors and THE JOURNAL and not those of the American Medical Association. \\\\\Reprint requests to Regenstrief Institute, 5th Floor RHC, 1001 W 10th St, Indianapolis, IN 46202 (Dr McDonald). Outline l REFERENCES Guidelines are popular these days. They are mentioned in journal articles [1,2,3] , editorials [4] , insurance company contracts, and federal legislation. The Institute of Medicine has dedicated two reports to the subject [5,6] . Unfortunately, the word guideline covers a broad spectrum of intellectual products. Some are hard to follow. They use weasel words instead of numeric thresholds or explicit criteria at their decision points and do not really tell you what to do. We say these are not decidable. Drug package inserts are notorious: "Serum electrolytes (particularly potassium), CO 2 , creatinine and BUN should be determined frequently during the first few months of Lasix therapy and periodically thereafter." [7] Guidelines for isoniazid prophylaxis, in contrast, are explicit and easy to follow [8] . Some are simple, describing the indications for a single action and requiring access to only a few variables for their execution. The Centers for Disease Control and Prevention guidelines for influenza vaccine are a good example [9] . Others are complex and define the behavior required to achieve a diagnostic or therapeutic goal (eg, the diagnosis of jaundice or the treatment of heart failure). These may require access to hundreds of variables for their execution. The HELP system algorithm for ventilator management of acute respiratory distress is the best example [10] . Guidelines vary in their validity--the degree we can trust they will guide us in the right direction. Some are pure opinion or the musings of "expert" committees (Woolf's class I guidelines [2] ). Others are products of formal processes and rooted in solid scientific data [2,11] . Some, like the rules reported in this issue of JAMA [12] , raise their validity to a new high by proving their benefit in a clinical trial. Page 1 of 5 Ovid: McDonald: JAMA, Volume 271(11).March 16, 1994.872-873 7/27/01 http://gateway2.ovid.com/ovidweb.cgi