NOTE TO READERS: When this project lost substantial funding at the end of 2018, I lost the ability to continue publishing criteria-driven news story reviews and PR news release reviews - once the bread-and-butter of the site going back to 2006. The 3,200 archived reviews, while still educational, are getting old and difficult for me to technically maintain on the back end of the website. So I am announcing that I plan to remove these reviews from the site by April 1, 2021. The blog and the toolkit - two of the most popular features on the site - will remain. If you wish to peruse the reviews before they disappear, please do so by the end of March 2021. After that date you may still be able to access them via the Internet Archive Wayback Machine -

Understanding medical tests: A new addition to our toolkit addressing sensitivity, specificity, and other core concepts

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Kevin Lomangino is the managing editor of He tweets as @KLomangino.

understanding medical tests

Hardly a day goes by without some media outlet making an impressive-sounding claim about the accuracy of a new medical test.

But as we repeatedly point out in our story reviews and blog posts, these messages often badly misrepresent what these tests are actually capable of, how they might perform in real-world situations, and how they might cause harm.

How can journalists and the public improve their understanding of medical tests and evaluate these claims more effectively?

We can start by getting a handle on some basic concepts in medical testing: sensitivity, specificity, and positive predictive value.

These concepts are crucial to understanding how often a test will correctly identify people with disease and how often it will miss them.

Just as important, they help clarify how often a test will generate a false-positive result — which can cause anxiety and lead to costly and invasive follow-up tests and procedures.

Unlike many news story headlines, I’m not going to pretend that medical tests are “simple” to understand.

But in a new addition to our toolkit published today, I brought in lots of case studies and examples that help illustrate core testing concepts–such as the difference between diagnosis and screening–and show why they are important.

CLICK HERE to read the new primer. 

I think some readers will come away shocked at the woefully superficial and inaccurate manner in which many news stories communicate about medical tests.

This primer provides some resources–and hopefully some inspiration–to do better.

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