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 )

Related Words

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