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
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Many have significant reservations about the safety and efficacy of the COVID vaccine, despite assurances from most experts that the benefits outweigh the risks.—Paul Sisson, San Diego Union-Tribune, 20 Sep. 2025 Many of Kennedy’s picks have expressed skepticism about the safety and efficacy of vaccines.—Erika Edwards, NBC news, 19 Sep. 2025 The opportunity lies in meeting demand with products that combine proven efficacy with the value of a beauty product rather than being treated as a simple commodity.—Fairchild Studio, Footwear News, 19 Sep. 2025 Forgetting even just one pill can negatively impact efficacy.—Pearl Pugh, Forbes.com, 19 Sep. 2025 See All Example Sentences for efficacy
Word History
Etymology
borrowed from Latin efficācia, from efficāc-, efficāx "capable of fulfilling a function, efficacious" + -ia-y entry 2
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