(Related concepts: absolute risk reduction, number needed to treat, and odds ratio.) The ratio (quotient) of the risk difference for the occurrence of an event in the group exposed to a given factor and the probability that this event will occur in the group not exposed to this factor. Note: Thus, if the results of a trial show that the probability of death is 25% in the control group and 10% in the experimental group, the relative risk reduction is (0.25 — 0.10) ÷ 0.25 = 0.6.

and • provides information on costs and financial impact. Note 2: The report may optionally discuss organisational considerations. Note 3: A “mini-HTA” may be as rigorous as an HTA report but typically has a restricted scope and so is quicker to produce. Note 4: Related terms include health technology, HTA report, rapid review, level of evidence