Calculating
Sensitivity

•How many times was the target disorder actually present?:
a+c

•How many of these times did the diagnostic test produce positive results?: a

–Note: We do
not count the number of times the diagnostic
test produced positive results when the target disorder was absent (b). We are only interested in the cases where target disorder was present .

•So what fraction of the total number of times the target disorder was present did the diagnostic test produced positive results?: a / (a + c)