efficacy

American  

[ef-i-kuh-see] / ˈɛf ɪ kə si /

Sometimes efficacity

noun

plural

efficacies

1. the capacity for producing a desired result or effect.

   Short, frequent periods of practice were shown to have greater efficacy than longer and less frequent ones.

2. a measure of the success of a vaccine or other pharmaceutical when used in the controlled environment of a clinical trial, as opposed to in the real world.

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efficacy British  

/ ˈɛfɪkəsɪ /

noun

1. the quality of being successful in producing an intended result; effectiveness

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Other Word Forms

• nonefficacy noun

Etymology

Origin of efficacy

First recorded in 1520–30; from Latin efficācia, from efficāc- (stem of efficāx ) “effective, effectual” + -ia, noun suffix; efficacious ( def. ), -y ³ ( def. )

Example Sentences

"The committee strives to balance the impacts on animals with benefits to people including assessing the safety and efficacy of medicines," he said.

From BBC

“We’re going to need to have all the efficacy of steroids with a clean side effect profile,” said Atlas Venture Partner Bruce Booth.

From The Wall Street Journal

Rather than seek more FDA approvals, it funded studies purportedly proving its efficacy for more common ailments such as anxiety, migraines and chronic nerve pain.

From The Wall Street Journal

"This new therapeutic approach to recovery needs to be moved into carefully designed human clinical trials to determine whether the efficacy seen in animal models translates to human patients," Dr. Pieper explained.

From Science Daily

It remains unclear whether subclade K will reduce the efficacy of this year’s flu shot.

From Los Angeles Times

Related Words

• adequacy
• competence
• effectiveness
• potency
• virtue