"Efficacy" is defined as: o Ability of an intervention to produce desired beneficial effect in expert hands and under ideal circumstances o In pharmacology, the ability of a drug, biologic, or device to produce desired therapeutic effect independent of potency (amount of the product needed for desired effect) - "Effect" is defined as the result produced by an action - Lack of efficacy/effect is therefore evidence of less than the expected effect of a product - There might be subpopulations that have a higher risk for lack of efficacy/effect; in order to identify such cases, one needs to consider types of events that may be reported in such situations for the specific product and indication.