topic Re: Sample size to meet specificity and sensitivity requirements in Discussions

Sample size to meet specificity and sensitivity requirements

Agustin — Thu, 08 Jun 2023 21:05:59 GMT

Hi, I'm trying to calculate the sample size required for my test to meet the sensitivity and specificity requirements.

I have a binary test that detects the presence of bacteria in water, if it's positive bacteria is present, if it's negative it is not present.

I would like my test to have

92% sensitivity (with 95% CI of 90-94%)

and

90% specificity (with 95% CI of 88-92%)

and I want the power to be 0.8

I want to know how many samples I need in order to meet this requirements, how many positive bacteria samples and negative bacteria samples.

How would I go about doing this calculation? I've had a look under DOE > Design Diagnostics > Sample Size and Power. But I'm still not clear on which I should be using and how.

Many thanks!

Re: Sample size to meet specificity and sensitivity requirements

peng_liu — Thu, 30 Sep 2021 00:56:09 GMT

I cannot find such feature in JMP. This subject is not my specialty, but I found this article Sample size estimation in diagnostic test studies of biomedical informatics is highly relevant.

Re: Sample size to meet specificity and sensitivity requirements

ih — Thu, 30 Sep 2021 13:16:17 GMT

If I understand your question correctly that isn't something you can do in DOE design. The sensitivity and specificity are properties of your test method itself. Your DOE can help to measure those properties, but it can't change how often your test indicates positive or negative given a true positive or negative which is what you would need to do in order to get a certain sensitivity or specificity.

Maybe I misinterpreted your question though?