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Clinical Review

Understanding sensitivity and specificity with the right side of the brain

BMJ 2003; 327 doi: https://doi.org/10.1136/bmj.327.7417.716 (Published 25 September 2003) Cite this as: BMJ 2003;327:716

Rapid Response:

Lies damned lies and sub-editors

The teaser paragraph presumably added by a sub-editor with a poorer
grasp of the concepts than the author has done the article a grave mis-
service by confusing sensitivity and PPV.
I did not find the diagrams helpful. For my money the best simple
explanation of these concepts is given in the book Clinical Chemistry
edited by Marshall. Read and understand.

Note that:
PPV is correlates with specificity and with disease prevalence.
NPV correlates with sensitivity and inversely with disease prevalence.

Good try by the author. I have tried to teach these concepts to
medical and science undergrads yearly for about 7 years using a problem
solving approach, and it is TOUGH.

Competing interests:  
None declared

Competing interests: No competing interests

03 October 2003
Paul G McIntyre
consultant virologists
ninewells hospital dundee DD1 9SY Scotland