The Difference Between Sensitivity and Specificity

Spin and snout is a nemonic that we use. Spin means that specific tests are good for ruling in diseases. And snout means that sensitive tests are good at ruling out diseases. So sensitivity tells you the chance that a diseased person will come up positive on the test. The specificity tells you the chances that a non-disease tested negative. But remember, it's more often predictive values that get at what we really want to know.