The<unk>  is the decrease in<unk>  of a given activity or treatment in relation to a control activity or treatment. It is the inverse of the number needed to treat.
In general,<unk>  is usually computed with respect to two treatments A and B, with A typically a drug and B a placebo (in our example above, A is a 5-year treatment with the hypothetical drug, and B is treatment with placebo, i.e. no treatment). A defined endpoint has to be specified (in our example: the appearance of colon cancer in the 5 year period). If the probabilities pA and pB of this endpoint under treatments A and B, respectively, are known, then the<unk>  is computed as pB-pA.
The inverse of the<unk> , NNT, is an important measure in pharmacoeconomics. If a clinical endpoint is devastating enough (e.g. death, heart attack), drugs with a low<unk>  may still be indicated in particular situations. If the endpoint is minor, health insurers may decline to reimburse drugs with a low<unk> .
Absolute risk reduction
Attributable risk
Statistical significance
Point prevalence
Number needed to treat
Bias of an estimator
Absolute deviation
Biased sample