Intended for healthcare professionals


Opening the black box of clinical judgment—an overview

BMJ 1999; 319 doi: (Published 13 November 1999) Cite this as: BMJ 1999;319:1279
  1. Lawrence L Weed, president (,
  2. Lincoln Weed, attorneyb
  1. a PKC Corporation, Box A-8, Burlington, Vermont 05401-1530, USA
  2. b Groom Law Group, 1701 Pennsylvania Avenue NW, Washington, DC 20006-5893, USA
  1. Correspondence to: L L Weed

    In all advanced healthcare systems, medical decision making depends on cognitive inputs from highly trained doctors. Yet those cognitive inputs fall short of what the practice of medicine requires. The reason is that doctors are expected to do the impossible—firstly, to recall and process complex information reliably under severe time constraints, and then to identify the decisions that patients would make for themselves were they fully informed. The inevitable outcome is that doctors' decisions too often cannot be justified in light of available knowledge, medical risk, cost, benefit, or patients' desires.

    The impossible is expected of doctors because we are socialised to rely on their acquired knowledge and cognitive abilities. But cognitive psychology has shown that the human mind normally functions by oversimplifying and filtering complex information. In contrast, modern electronic tools, if properly designed, can empower the mind to systematically consider all available details and their possible combinations. A new division of intellectual labour in medicine is therefore possible—a division between electronic tools that retrieve and process information, and users who apply judgment and values to arrive at medical decisions.

    Summary points

    Medical decision making requires combinatorial analysis to comprehend patients' uniqueness and avoid harmful, unnecessary trial and error

    Combinatorial analysis combines numerous, simple, inexpensive observations, tests, and procedures on a patient with medical knowledge to identify all individually relevant options, and the pros and cons of each for the patient

    The apparent difficulties of a combinatorial approach—gathering comprehensive data and linking it with the medical knowledge base—are avoidable when properly designed software tools are habitually used

    The actions of caregivers and the medical knowledge they use must be subject to effective feedback, which requires medical records with a problem oriented structure

    New systems are needed not only to improve cognitive inputs to medical decision making but also to improve manual …

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