effectiveness

[ 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. Compare efficacy ( def 2 ).

Other Words From

• sub·ef·fec·tive·ness noun
• su·per·ef·fec·tive·ness noun
• un·ef·fec·tive·ness noun

Word History and Origins

Origin of effectiveness¹

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

Example Sentences

Alexandra Syphard — one of the first researchers to study the effectiveness of home hardening and defensible space in real wildfires in the early 2010s — said it’s somewhere in the middle.

From Los Angeles Times

The Los Angeles Board of Supervisors quickly and quietly rejected a chance to discuss improvements in governance and effectiveness.

From Los Angeles Times

Elise accepts that those opposed to the bill have questions about the effectiveness of these safety measures, and the ethics of assisted dying.

From BBC

In order to gauge the law’s effectiveness, study authors examined the prevalence of chemicals found in blood and urine samples collected by the Centers for Disease Control and Prevention.

From Los Angeles Times

Business leaders have long been skeptical of Proposition 65’s effectiveness.

From Los Angeles Times

Related Words

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