Number Needed to Harm Nomogram
Click and drag the green, blue, and red arrows to change the control event rate (CER), relative risk increase (RRI), and number needed to harm (NNH) or type the values into 1 or more of the boxes. Hit Enter on your keyboard to calculate the number needed to harm. Click the 3 “Adjust Scale” lines at the bottom to choose from a larger or smaller range of values.