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Absolute risk reduction/increase


The absolute arithmetic difference in rates of bad outcomes between experimental and control participants in a trial, calculated as the experimental event rate (EER) and the control event rate (CER), and accompanied by a 95% CI. Depending on circumstances it can be reduction in risk (death or cardiovascular outcomes, for instance, in trials of statins), or an increase (pain relied, for instance, in trials of analgesics). An example might help.