efficacy

[ ef-i-kuh-see ]

noun

, plural ef·fi·ca·cies.

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. Compare effectiveness ( def 3 ).

efficacy

/ ˈɛfɪkəsɪ /

noun

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

Other Words From

• non·ef·fi·ca·cy noun

Word History and Origins

Origin of efficacy¹

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

In their new study, the team wanted to confirm the drug's efficacy in a more rigorous comparison against a placebo using a double-blind randomized clinical trial design.

From Science Daily

Then the team conducted a series of efficacy and dosing trials with mice:

From Science Daily

The Michigan-led team plans to continue follow-up with participants to determine the long-term safety and efficacy of recycled pacemakers.

From Science Daily

Shortly following the Phase 1 trial, a Phase 2a trial will be conducted to further establish the safety and begin to define the efficacy of EV25.

From Science Daily

With the new machine learning methodology, we can now extend our work to investigate how drug-carrying nanoparticles interact with blood proteins and how those interactions change the efficacy of the drug carriers, Häkkinen concludes.

From Science Daily

Related Words

• adequacy
• competence
• effectiveness
• potency
• virtue