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

Yet Novo Nordisk plans to avoid the mistakes that hurt it during the last round, and will seek to hold on to its early lead by emphasizing the effectiveness of its pill.

From The Wall Street Journal • Apr. 1, 2026

Despite doubts about their effectiveness, Minicircle’s gene therapy and others like it are available at an increasing number of clinics across the world.

From Slate • Mar. 30, 2026

Users hit back at Papperger's comments with jokes and memes highlighting the effectiveness of Ukrainian drones and anti-drone defences.

From Barron's • Mar. 29, 2026

Gaining a better understanding of how these drugs are stored and distributed inside cells could lead to more personalized treatment strategies, improving effectiveness while reducing resistance and relapse.

From Science Daily • Mar. 27, 2026

The effectiveness of machine guns as defensive weapons kept both sides from achieving a breakthrough and helped prolong the deadlock of trench warfare that immobilized the Western Front.

From "The War to End All Wars: World War I" by Russell Freedman

Related Words

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