A preliminary qualitative analysis of the heuristic “Don’t think zebras”

Stéphanie Van Droogenbroeck

Onderzoeksoutput: Meeting abstract (Book)


Heuristics are part of scientific discovery. We will show that medical diagnostics -i.e. looking for a diagnosis- is an example of scientific discovery. This means that a study of heuristics is indispensable in the research on medical diagnostics.
"Do not think zebras" is a well-known heuristic in medical which means that physicians need to think of a common disease first instead of a rare pathology. This heuristic is popular in scientific research, but it is not clear if physicians use them in a diagnostic practice.
Four physicians (one GP, two urologists and one neurologist) in Brussels (Belgium) were asked to diagnose two imaginary patients (patient 1 has asthma and meningitis which are common diseases for that particular patient; and patient 2 has cushings syndrome, which is a rare disease considering the symptoms of patient 2). A patient history was given by the interviewer and the physicians could ask questions on laboratory or radiology results. A close analysis of the transcripts of the semi structured interviews were used to clarify the decision-patterns that led to the actual diagnoses.
Three physicians consider more possible diagnoses with the patient with the uncommon cushings syndrome.
They all diagnosed meningitis, but only one physician was looking in the right direction for diagnosing patient 2. Asthma was diagnosed by a single physician.
Firstly, it may be clear that the "do not think zebras" heuristic works in practice. The more common diagnosis was found. A possible explanation is the heuristic, but another possibility is that meningitis should be recognized much faster to avoid that the patient dies. Physicians are trained to discover which symptoms are life threatening in the short run, i.c. meningitis, and which are not, i.c. cushings. This could also explain why asthma was only found by one physician. If a patient presents himself with meningitis and mild asthma, it is more important to treat him for the meningitis first.
Secondly, the usage of this rule of thumb implies some dangers- such as late referral from the GP to a specialist. We will discuss this by using a hypothetical neurological patient and discussing the relevant literature on delayed referral.
Finally, we will discuss some results of the ongoing study on medical diagnostics, and the use of heuristics in clinical practice to clarify the study discussed in this talk.
Originele taal-2English
Titel4th International Philosophy of Medicine roundtable- University of the Basque Country- San Sebastian
StatusPublished - 2011
EvenementUnknown -
Duur: 1 jan 2011 → …

Publicatie series

Naam4th International Philosophy of Medicine roundtable- University of the Basque Country- San Sebastian


Periode1/01/11 → …


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