efficacy

play

noun ef·fi·ca·cy \ˈe-fi-kə-sē\

Definition of efficacy

plural

efficacies

: the power to produce an effect

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Examples of efficacy in a Sentence

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. 2003
Vaccines 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 of efficacy from the Web

The curriculum is specifically designed toward fostering character development and responsibility geared to elevating individual empowerment, efficacy and self-esteem.

— miamiherald, "Success for Miami Rowing Club, Ransom Everglades sailing", 4 June 2017
Additionally, rarely in use of force situations is there agreement from all the parties involved as to the appropriateness, efficacy, or necessity of its use.

— lisa gutierrez, kansascity, "Police officer who slammed young woman to the ground in viral video is exonerated", 2 June 2017
The comment and the talking points were meant to undercut the efficacy of the Paris agreement, a claim that Reilly says is wrong.

— dan merica, CNN, "Author of MIT climate study says Trump got it wrong", 2 June 2017
In addition, sunscreen efficacy decreases in the water or with sweating.

— kerry hanson, Smithsonian, "How Sunscreen Protects Your Skin’s DNA", 31 May 2017
And despite their diminishing efficacy, over-the-counter lice shampoos remain the first response recommended by most doctors, health plans and even the American Academy of Pediatrics.

— karen weintraub, Scientific American, "Revenge of the Super Lice", 29 May 2017
Still, Lewin is skeptical of its efficacy, in part because the herbal proportions aren’t labeled.

— gordy megroz, Bloomberg.com, "This Sports Gel Built a Cult Following Among Extreme Athletes", 24 May 2017
As much as his efficacy in front of the goal, and the characteristic imagination in his play, his undimmed appetite for the battle has impressed.

— rory smith, New York Times, "With Success in England, Zlatan Ibrahimovic Strikes a Blow Against Snobbery", 27 Feb. 2017
Data such as this supports the belief in and bolsters the efficacy of familial searching to produce valuable leads.

— eli rosenberg, New York Times, "Conflicting Views on a Wider Police Use of DNA", 10 Feb. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'efficacy'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.