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. )

Example Sentences

Kennedy repeatedly defended his record in heated exchanges with senators from both parties and questioned data that show the effectiveness of vaccines.

From Los Angeles Times

The letter accused Kennedy of stacking the agency with “political ideologues” and manipulating data on vaccine effectiveness.

From Salon

In the testy appearance before the Senate Finance Committee, Kennedy repeatedly defended his record in heated exchanges with senators from both parties and questioned data that show the effectiveness of vaccines.

From Los Angeles Times

It uses a unit of measurement called the "Qaly" - the "quality-adjusted life year", which gauges drug effectiveness in terms of how much it would cost to give you a year of healthy life.

From BBC

“There are many studies, some showing 87% effectiveness,” he claimed, “against serious disease and death.”

From Salon

Related Words

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