
Understanding medical tests: sensitivity, specificity, predictive value (2018) - akbarnama
https://www.healthnewsreview.org/toolkit/tips-for-understanding-studies/understanding-medical-tests-sensitivity-specificity-and-positive-predictive-value/
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avalys
This is not just medical tests - you use the same criteria to evaluate any
binary classifier.

“Precision and recall” are positive predictive value and sensitivity,
respectively.

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kryogen1c
saying a test has 85% accuracy tells you nothing about the results of that
test. not being hyperbolic - literally nothing. simple proof:

i develop a test for disease X and give it to 1 billion walking around grocery
stores in the whole world. it is 85% accurate. results are 200 million people
are positive? how many of those people actually have disease X? do you have a
guess?

disease X i was testing for was death. every single positive test was wrong.
how close was your guess?

you must, at a minimum, know test accuracy _as well as_ disease prevalence to
form a statistical guess. death is prevalent in 0% of alive people, so test
accuracy is worthless.

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bugzz
As long as we are fairly confident about the specificity and sensitivity of
the test, then it DOES tell us something, even if those numbers are as low as
85%.

Here's the flaw in your proof - If the test has 85% specificity, then the
chance of 200 million positives is essentially 0% (you'd get ~150 million if
no one really has the disease). Getting a result of 200 million positive means
either you DO have a significant number of true positives (50 million), or
your 85% number for specificity was wrong.

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matheusmoreira
Wikipedia article on the subject:
[https://en.wikipedia.org/wiki/Sensitivity_and_specificity](https://en.wikipedia.org/wiki/Sensitivity_and_specificity)

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mlthoughts2018
Using my VPN, this site says access is not allowed. It seems very scammy /
low-quality as a result.

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SubiculumCode
Hits, misses, correct rejections, false alarms, in memory research lingo. Can
I get a d-prime?

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ageitgey
This site blocks visitors from the UK.

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neonate
[https://archive.md/Glbh8](https://archive.md/Glbh8)

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lean_industries
This is amazing +1

