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

But that tactic no doubt exists, particularly with the less scrupulous agents out there,” said Andy Panko, a certified financial planner who is tracking IUL policy claims and testing their effectiveness in a continuing project.

From MarketWatch • May 27, 2026

Sticking with existing rules could “impact the overall index’s effectiveness as a benchmark,” S&P Dow Jones Indices suggested in the launch of its consultation.

From The Wall Street Journal • May 27, 2026

Reports of children in Australia being able to access sites supposedly blocked for under-16s have raised concerns over the law's effectiveness.

From BBC • May 25, 2026

In other remarks, he emphasized what he called “lethality over likability,” arguing that military leadership must prioritize combat readiness and battlefield effectiveness over cultural or institutional concerns.

From Salon • May 24, 2026

The Forest Biology Division agreed to modify the spraying program in every possible way short of destroying its effectiveness, in order to reduce risks to the fish.

From "Silent Spring" by Rachel Carson

Related Words

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