In the planner's view, Rumsfeld had two goals: to demonstrate the efficacy of precision bombing and to "do the war on the cheap."—Seymour M. Hersh, New Yorker, 7 Apr. 2003Vaccines exist, but their efficacy against aerosolized plague is unknown.—Sharon Begley et al., Newsweek, 8 Oct. 2001… efficacy does not have to be demonstrated before homeopathic products are marketed.—Alison Abbott et al., Nature, 26 Sept. 1996
questioned the efficacy of the alarms in actually preventing auto theft
Recent Examples on the WebOne-two punch While such new chemical tricks can bypass resistance mutations—at least for a time—researchers are increasingly looking to combination therapies, which could help prevent resistance from developing in the first place while boosting efficacy.—Beth Mole, Ars Technica, 5 Aug. 2024 The marina is one of five spots on the river where scientists this summer are studying he efficacy of various herbicides in an effort to control the weeds explosive growth.—Edmund H. Mahony, Hartford Courant, 5 Aug. 2024 While the initial protection appeared strong, the efficacy dropped to between 30% and 50%.—Andrew Joseph, STAT, 1 Aug. 2024 The primary efficacy objective of the study was clinically meaningful differences in pain (a decrease in pain score by two or more points) and function (an eight or more point increase in KOOS score) at 12 months.—New Atlas, 28 July 2024 See all Example Sentences for efficacy
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'efficacy.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Word History
Etymology
borrowed from Latin efficācia, from efficāc-, efficāx "capable of fulfilling a function, efficacious" + -ia-y entry 2
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