do you know the formulas to calculate specificity, sensitivity, PPV, NPV,..?














First, think of the 2X2 box: TP, FP on top and FN, TN on bottom.. disease is on top of the box, and test is on the side; Simple rule to remember: "trues" on top/everything else...

Sensitivity=TP/TP+FN
Specificity=TN/TN+FP
PPV=TP/TP+FP
NPV=TN/TN+FN
Odds ratio=TP/FP divided by FN/TN = (TP)(TN)/(FP)(FN)
Relative Risk=TP/(TP+FP) divided by FN/(FN+TN)