efficacy
noun
[ ˈɛfɪkəsi ]
• the ability to produce a desired or intended result.
• "there is little information on the efficacy of this treatment"
Similar:
effectiveness,
success,
successfulness,
productiveness,
fruitfulness,
potency,
power,
benefit,
advantage,
value,
virtue,
use,
usefulness,
effectuality,
constructiveness,
Origin:
early 16th century: from Latin efficacia, from efficax, efficac- (see efficacious).