From Longman Dictionary of Contemporary Englishefficacyef‧fi‧ca‧cy /ˈefəkəsi/ noun [uncountable + of] formalEFFECTIVE the ability of something to produce the right result SYN effectiveness OPP inefficacy
Examples from the Corpus
efficacy• Sufficient data on safety and efficacy of long-term use of Ritalin in children are not yet available.• Each is adorned with silken cloths and has its tusks shod with iron for the greater efficacy of killing criminals.• Struan, because of its direct descent from a traditional ritualistic practice, still retains a trace of sacramental efficacy.• Franz Kafka perfectly exemplifies the efficacy of art in counteracting emotional wounds, if not in healing them.• This effect, essentially an increase in the efficacy of transmission between pre- and postsynaptic cells, was termed potentiation.• Salmeterol could therefore reduce the efficacy of salbutamol when the two are given in combination.• Evaluate vaccine efficacy and the costs and benefits of vaccination programs for emerging infections.• It is a controversy over the issues of risk versus efficacy. 