efficaciousness

/ˌɛfɪˈkeɪʃəsnəs/
noun
  1. The quality of being able to produce the intended result; effectiveness.
    • The efficaciousness of the new teaching method was proven by higher test scores.
    • Doctors studied the efficaciousness of the vaccine in preventing the disease.
    • The team doubted the efficaciousness of the plan, but it worked perfectly.
Antonyms