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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Like the probiotics claiming to heal your gut, vaginal ones haven’t undergone the stringent safety and efficacy testing necessary for FDA approval.—Erica Sloan, SELF, 7 July 2025 Testers considered performance across four primary categories: efficacy, texture and experience, fragrance, and packaging.—Jennifer Hussein, Allure, 30 June 2025 The schedule is developed and regularly updated by the ACIP, a longstanding panel of medical and public health experts who evaluate vaccine safety, efficacy, and disease prevalence.—Gabe Whisnant, MSNBC Newsweek, 25 June 2025 Instead, the best hope for more energy-efficient AI may lie in the cost efficacy of using less energy.—Cnn.com Wire Service, Mercury News, 25 June 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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