effectiveness

Rarely ef·fec·tiv·i·ty

[ih-fek-tiv-nis, ee-fek‐]

noun

1. the quality of producing an intended or desired result.

   For maximum effectiveness of your weight loss plan, you need to combine exercise with a healthy diet.

2. the quality of producing a deep or vivid impression.

   We were struck by the evident appeal and effectiveness of these short, dramatic, upbeat video stories.

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

Other Word Forms

• subeffectiveness noun
• supereffectiveness noun
• uneffectiveness noun

Word History and Origins

Origin of effectiveness¹

First recorded in 1600–10; effective ( def. ) + -ness ( def. )

Related Words

• capability 
• efficacy 
• efficiency 
• potency 
• power 
• success