different between efficacy vs impact

English

Etymology

From Old French efficace, from Late Latin effic?cia (“efficacy”), from effic?x (“efficacious”); see efficacious.

Pronunciation

• IPA^(key): /??f.?.k?.si/

Noun

efficacy (usually uncountable, plural efficacies)

1. Ability to produce a desired effect under ideal testing conditions.
   • 2005, Flay et al. Standards of Evidence: Criteria for Efficacy, Effectiveness and Dissemination DOI: 10.1007/s11121-005-5553-y

     Efficacy refers to the beneficial effects of a program or policy under optimal conditions of delivery, whereas effectiveness refers to effects of a program or policy under more real-world conditions.

2. Degree of ability to produce a desired effect.
   • 1996, Moskovich, Patent application PCT/US1996/003658

     Toothbrush with improved efficacy

Synonyms

• efficacity

Related terms

Translations

Further reading

• efficacy in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913.
• efficacy in The Century Dictionary, New York, N.Y.: The Century Co., 1911.

English

Etymology

From Latin imp?ctus, perfect passive participle of imping? (“dash against, impinge”).

Pronunciation

• (noun): enPR: im?p?kt, IPA^(key): /??mpækt/
• (verb): enPR: im-p?kt?, IPA^(key): /?m?pækt/
• • Rhymes: -ækt

Noun

impact (countable and uncountable, plural impacts)

1. The striking of one body against another; collision.
2. The force or energy of a collision of two objects.

3. (chiefly medicine) A forced impinging.

4. A significant or strong influence; an effect.

Usage notes

• Adjectives often applied to "impact": social, political, physical, positive, negative, good, bad, beneficial, harmful, significant, great, important, strong, big, small, real, huge, likely, actual, potential, devastating, disastrous, true, primary.
• The adposition generally used with "impact" is "on" (such as in last example in section above)
• There are English speakers who are so averse to the verb sense that they have become hypersensitive to the use of the figurative noun sense, with a low threshold for labeling such use as overuse (cliché). In defensive editing, the solution is to replace the figurative noun sense with effect and the verb sense with affect, which nearly always produces an acceptable result. (Rarely, a phrase such as "the impact of late effects" is better stetted to avoid "the effect of [...] effects".)

Derived terms

Related terms

• impinge

Translations

Verb

impact (third-person singular simple present impacts, present participle impacting, simple past and past participle impacted)

1. (transitive) To collide or strike, the act of impinging.

   When the hammer impacts the nail, it bends.

2. (transitive) To compress; to compact; to press into something or pack together.

   The footprints of birds do not impact the soil in the way those of dinosaurs do.

3. (transitive, proscribed) To influence; to affect; to have an impact on.

   I can make the changes, but it will impact the schedule.

4. (transitive, rare) To stamp or impress onto something.

   Ideas impacted on the mind.

Usage notes

Some authorities object to the verb sense of impact meaning "to influence; to affect; to have an impact on". Although most verbification instances in English draw no prescriptive attention, a few do, including this one. To avoid annoying those readers who care, one can replace the verb sense with affect, which nearly always produces an acceptable result. See also the usage note for the noun sense.

Derived terms

• impaction
• impactor

Translations

French

Etymology

From Latin, see above.

Pronunciation

• IPA^(key): /??.pakt/

Noun

impact m (plural impacts)

1. (literally or figuratively) impact

Further reading

• “impact” in Trésor de la langue française informatisé (The Digitized Treasury of the French Language).

Romanian

Etymology

From French impact, from Latin impactus.

Noun

impact n (plural impacturi)

1. impact

Declension