absolute risk increase

Absolute Risk Increase

The increase in the likelihood of an event’s occurrence when a population is exposed to a determined factor—e.g., a particular toxin or other hazard, pathogen, therapy, etc.—as compared to a control population not exposed to the factor of interest.

absolute risk increase

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ARI

A measure of the negative effect of an intervention or treatment in a clinical trial. It consists of the number of adverse events found in the experimental group, minus the number of adverse events in the control group. It is the opposite of the “absolute benefit increase.”