Perspectives in Biology and Medicine

DIAGNOSIS AS A SKILL: A CLINICAL PERSPECTIVE THOMAS A. PARRINO* and RUDOLPH MITCHELLt The three main tasks of the clinician . . . are diagnosis, prognosis, and treatment. Of these diagnosis is byfar the most important, for upon it the success of the other two depends.—Ryle [1] Introduction and Definition of Terms The word diagnosis is derived from the Greek words dia (through, between) and gignoskein (to know). Webster's Twentieth Century Dictionary defines diagnosis as follows: 1.The act or process of determining the nature of a diseased condition by examination. 2.A careful examination of the facts to determine the nature of a thing. 3.The decision or opinion resulting from such examination or investigation. Physicians learn diagnosis as they practice medicine [1—5]; some become better diagnosticians than others [6, 7]. How do effective clinicians learn to move so adroitly from data gathering to diagnosis? What guides their actions as they conduct their daily clinical investigations? It is the purpose of this essay to review the current status of our understanding of clinical diagnosis. In so doing, a number of questions will be raised: Is there a "general" diagnostic process used by all clinicians ? Is it possible to distinguish good diagnosticians from bad ones? Is it possible to teach cognitive diagnostic skills to young physicians? In order to address these questions, two general areas will be examined: 1.Recent developments in research on clinical diagnosis, with illustrative examples from disciplines outside medicine. 2.Applications of these developments in clinical medicine: medical practice, medical education, and the evaluation of clinical performance. ?Section of General Internal Medicine, Veterans Administration Hospital—Davis Park, Providence, Rhode Island 02908, and Division of Biology and Medicine, Brown University. tOffice for Educational Development, Harvard Medical School, 260 Longwood Avenue, Boston, Massachusetts 02115.© 1989 by The University of Chicago. AU rights reserved. 0031-5982/90/3301-0648$01 .00 18 I Thomas A. Panino and Rudolph Mitchell ¦ Diagnosis as a Skill The Link between Cognitive Science and the Science ofDiagnosis Modern studies of diagnosis were inspired by the idea that the diagnostic process should be viewed as a form of scientific inquiry rather than an empirical exercise [8]. In the 1950s, Ledley and Lusted [9] examined the probabilistic basis of diagnosis. Feinstein drew on the principles of traditional logic and statistical analysis [10]. Weinstein and Fineberg introduced the principles of formal decision analysis to the clinical environment [H]. Eddy and Clanton [12] broke down the diagnostic process into a series ofsteps, apparently governed by heuristics, or rules of thumb [13]. Researchers on artificial intelligence drew on their own studies of a generic problem-solving process [14, 15] to understand and explain the "clinical problem-solving" behaviors of physicians [1621 ]. More recently, the results of research carried out by cognitive psychologists have suggested that diagnostic thinking is dependent upon context-specific knowledge structures. Methodologies for the Study ofMedical Diagnosis Research into the cognitive aspects ofdiagnosis has been influenced by efforts in several fields: psychology, mathematics, artificial intelligence, linguistics, anthropology, decision theory, philosophy, social judgment theory, and neuroscience [22-25]. This has brought techniques of "disciplined introspection" into the clinic. These techniques can be divided into two major categories of analysis: declarative analysis and functional analysis. Declarative Analysis Declarative analysis usually centers on some sort of debriefing procedure ("stimulated recall") that takes place after a physician-subject has performed a diagnostic interview as part of a case protocol. Such protocols often involve simulated patients, and are either video- or audiotaped . As the tapes are played back, the physician-subjects describe how they reasoned through the case. These introspective methods (also known as "think aloud reporting") have furnished insight into the nature of clinical expertise [26-29]. Functional Analysis Functional analysis focuses on diagnostic actions (what doctors do) rather than descriptions of those actions (what they say they do) [25]. In one form of functional analysis, standardized patients record the physician 's actions on checklists after the clinical encounter [30, 31]. Other Perspectives in Biology and Medicine, 33, 1 ¦ Autumn 1989 \ 19 functional techniques include oral examinations, evaluation by observers , computerized case protocols, and paper-and-pencil tests of diagnostic skill—"patient management problems" [32-34]. Medical record audits have...