> relative risk reduction [...] “is just another way of lying.”<p>> You read that a new drug reduces your chance of dying from Ryantastic syndrome by 40 percent. Here’s what that means in practice: if 10 in 100,000 people normally die from Ryantastic syndrome, and everyone takes the new drug, only 6 in 100,000 people will die from Ryantastic syndrome. Now let’s think about it from an NNT perspective.<p>> For 100,000 patients who took the new drug, four deaths by Ryantastic syndrome were avoided, or one per 25,000 patients who took the drug. So the NNT is 25,000; that is, 25,000 patients must take the drug in order for one death-by-Ryantastic to be avoided. Ideally, you also want to know the NNH, or “number needed to harm.”<p>> Let’s say that 1 in 1,000 patients who take the new drug suffer a particular grievous side effect. In that case, the NNH is 1,000, while the NNT is 25,000. Suddenly, the decision seems a lot more complicated than if you’re just told the drug will lower your chance of dying from Ryantastic syndrome by 40 percent.