effectiveness

American  

[ih-fek-tiv-nis, ee-fek‐] / ɪˈfɛk tɪv nɪs, iˈfɛk‐ /

Rarely effectivity

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.

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Other Word Forms

• subeffectiveness
  noun
• supereffectiveness
  noun
• uneffectiveness
  noun

Etymology

Origin of effectiveness

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

Example Sentences

See Examples For:

effectiveness

Meteorologists, however, are divided over the effectiveness of the practice.

From BBC ● Sep. 23, 2026

Gen. Harold G. Moore, who commanded a cavalry unit at the late 1965 Ia Drang battle, fretted how the war was “devastating to the morale and effectiveness of every American unit in combat.”

From Salon ● Sep. 20, 2026

The effectiveness of GLP-1 weight loss drugs sparked a panic that October, hitting purveyors of caloric food and beverages such as Coca-Cola, Pepsico, Yum Brands and Mondelez.

From The Wall Street Journal ● Sep. 18, 2026

NPR described the outcome as a striking rejection of the FDA’s stance, pointing out that every one of these compounds lacks the large, well-controlled clinical trials required to prove safety and effectiveness in humans.

From MarketWatch ● Sep. 17, 2026

The psychologist Nalini Ambady once gave students three ten-second videotapes of a teacher—with the sound turned off—and found they had no difficulty at all coming up with a rating of the teacher’s effectiveness.

From "Blink" by Malcolm Gladwell

Related Words

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