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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There are safety measures in place to protect against the use of harmful mercury or lead in products, for example, but brands don’t have to prove the efficacy of cosmetic ingredients or submit drug requests with clinical studies to the FDA or any other regulatory body.—Kara Nesvig, Allure, 24 Apr. 2025 After determining the most promising options, researchers then adjusted the guns to calculate an equation focused on a shield stack’s efficacy and performance.—Andrew Paul, Popular Science, 24 Apr. 2025 This skews data, limits efficacy insights and ultimately delays market access.—Aman Gupta, Forbes.com, 22 Apr. 2025 The purpose of that study was to compare cost to efficacy, not to tabulate causations.—Wes Siler, Outside Online, 19 Apr. 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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