Quiz HN: Test your biases
7 comments
Please provide more information. What is the specificity of each test? What is the sensitivity of each test? And how virulent is the disease? And how expensive is each test?
http://en.wikipedia.org/wiki/Sensitivity_and_specificity
http://www.nhhealthcost.org/costByProcedure.aspx
http://en.wikipedia.org/wiki/Sensitivity_and_specificity
http://www.nhhealthcost.org/costByProcedure.aspx
That's pretty much the right answer.
Let's say all tests cost the same and are 99% specific. Test X is at least 70% sensitive. Test Y and Z have unknown sensitivity.
Let's say all tests cost the same and are 99% specific. Test X is at least 70% sensitive. Test Y and Z have unknown sensitivity.
All good tests should be strongly correlated with the presence/absence of swine flue, and hence correlated with each other. So either tests X/Y are broken, or test Z is broken. Or both.
We need to figure out which before answering the question.
We need to figure out which before answering the question.
My first instinct is to add test Z. Since Y correlates well with X, Z would provide more information.
But if Y is correlated to X, that might indicate something about its sensitivity.
But if Y is correlated to X, that might indicate something about its sensitivity.
If there are tests for a binary result (has cow-flu/does not have cow-flu) that are not correlated, one or both of the tests is bad. Further information could confirm or negate the choice of Y or Z (or sticking only with X).
Do you add test Y or test Z?