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

"Farmers often expect immediate results and sometimes use only one type of biofertiliser, which limits effectiveness," he said.

From Barron's • Jun. 16, 2026

However, in an analysis of two popular BIP models, the National Institute of Justice concluded that their effectiveness was mixed.

From Slate • Jun. 15, 2026

"It was always made explicit in the deal that the terms of the deal would expire… The sunset clauses in effect nullify their effectiveness," he argues.

From BBC • Jun. 13, 2026

The effectiveness of the recovery and deployment of the electrical system is not taken into account.

From BBC • Jun. 10, 2026

How a piece of rhetoric sounds—and this applies just as much whether it is heard out loud or scanned by the inner ear while being read on the page—is vital to its effectiveness.

From "Words Like Loaded Pistols" by Sam Leith

Related Words

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