as in effectiveness
the power to produce a desired result
questioned the efficacy of the alarms in actually preventing auto theft
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Recent Examples of efficacy
So, any vaccine safety and efficacy trial includes children who are getting the entire vaccine schedule in addition to the vaccine being tested, providing information on cumulative effects with every new addition.
—
ArsTechnica, 25 June 2025
In the morning, CDC staff presented data on COVID-19 vaccines, showing safety and efficacy as well as a reduction in hospitalizations and deaths.
—Mary Kekatos, ABC News, 25 June 2025
Issues like homelessness, gas prices, public transit, the cost of living and the efficacy of state government are relentlessly portrayed as unique, catastrophic failings.
—Deandre Evans, Mercury News, 25 June 2025
Operational Scale and Supply Chain Flexibility Operating 905 warehouses worldwide, including 624 in the U.S., Costco leverages its pricing advantage through extremely thin margins and the efficacy of its private-label brand, Kirkland Signature.
—Trefis Team, Forbes.com, 24 June 2025
See All Example Sentences for efficacy
ArsTechnica, 25 June 2025
In the morning, CDC staff presented data on COVID-19 vaccines, showing safety and efficacy as well as a reduction in hospitalizations and deaths.
—Mary Kekatos, ABC News, 25 June 2025
Issues like homelessness, gas prices, public transit, the cost of living and the efficacy of state government are relentlessly portrayed as unique, catastrophic failings.
—Deandre Evans, Mercury News, 25 June 2025
Operational Scale and Supply Chain Flexibility Operating 905 warehouses worldwide, including 624 in the U.S., Costco leverages its pricing advantage through extremely thin margins and the efficacy of its private-label brand, Kirkland Signature.
—Trefis Team, Forbes.com, 24 June 2025
See All Example Sentences for efficacy
Recent Examples of Synonyms for efficacy
efficiency
Noun
-
Cook enjoyed a career year that boasted efficiency and saw his touchdowns triple from 2023 (6) to 2024 (18).—
The Athletic NFL Staff,
New York Times,
8 July 2025
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Private equity firms have also circled some linear assets in recent years, looking to leverage their recurring subscription revenues and proficiencies in finding efficiencies.—
Alex Weprin,
HollywoodReporter,
8 July 2025
Cite this Entry
“Efficacy.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/efficacy. Accessed 13 Jul. 2025.
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