REPLY
Medical Heuristics
Clement J. McDonald, MD
1 July 1996 | Volume 125 Issue 1 | Page 78
IN RESPONSE:
Dr. Oetgen asks, "How do we start cataloging heuristics?" Collecting all the available aphorisms is a reasonable way to begin, but it is not enough. First, aphorisms rarely speak clearly enough to unambiguously guide decisions. In fact, one aphorism cited by Dr. Oetgen—primum non nocere—can be used to defend treating or not treating, depending on what you believe about which choice constitutes harm. A necessary second step is to generate rules that are precise enough to be applied and tested. The Zebra Rule, for example, might be recast as a rule about prevalence; for example, "work up the diseases in the differential with prevalences of greater than 1:100 before you work up those with prevalences less than 1:1000." I am sure this rule could be better stated, but even this formulation could be tested and improved with feedback.
Second, many important heuristics will not be identified if we limit our consideration to aphorisms. Careful analysis of our day-to-day decisions and the assumptions that underlie them will reveal many more. Welch and colleagues [1] published a perfect example of their statistical justification for the common heuristic that leads us to treat the young more aggressively than the old. The young gain more benefit from such treatment. For example, we should ask what heuristics guide pain management. Is the argument about addiction valid? What made us decide that vitamin B12 injections, as well as the physicians who gave them, were bad? We may have been wrong [2].
Dr. Gerber points out that we have been scammed by Sutton or by whomever quoted him. As he suggests, one option is to rename Sutton's Law as Dock's Law, but we pay a high price in color for our increased accuracy. Several physicians wrote to me directly, with thanks for confirming their belief that there is more to medicine than what we know of science. One writer also pointed out the error in my statement about Sutton. He thought it was an Escherian reinforcement of the need to critically analyze lore and accepted practice. False assumptions lurk everywhere.
Clement J. McDonald, MD
Regenstrief Institute for Health Care
Indianapolis, IN 46202
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Author and Article Information
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Regenstrief Institute for Health Care, Indianapolis, IN 46202
1. Welch HG, Albertsen PC, Nease RF, Bubolz TA, Wasson JH. Estimating treatment benefits for the elderly: the effect of competing risks. Ann Intern Med. 1996; 124:577-84.
2. Naurath HJ, Joosten E, Riezler R, Stabler SP, Allen RH, Lindenbaum J. Effects of Vitamin B12, folate, and Vitamin B6 supplements in elderly people with normal serum vitamin concentrations. Lancet. 1995; 346:85-9.
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