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Affect and Effect

Commonly Confused Words


Affect and Effect

Affect is usually a verb meaning to influence. Effect is usually a noun meaning result. When used as a verb, effect means to cause.

NOTE: If you're in a professional field related to psychology or psychiatry, you are probably familiar with a special use of affect (with stress on the first syllable) as a noun meaning "an expressed or observed emotional response." However, this technical term seldom appears in everyday (non-technical) writing.


  • Peace is a natural effect of trade. War affects trade in various ways.

  • In London, the weather would affect me negatively. The constant drizzle had a bad effect on my disposition.

  • If you want to effect change in Washington, you have to vote.


"In a table entitled Excessive vitamin intake, which accompanied the article, Watchdogs to set limits on vitamin intake (page 7, August 30), it was said that boron 'might effect reproduction.' No such miracle supplement is yet on the market. 'Affect' was the intended word."
(Corrections and Clarifications, The Guardian, September 3, 2002)

Usage Notes:

  • "Confusion concerning the use of these two words stems from the fact that anything that affects something else has an effect on it.

    "However, the verb meanings of the two words differ widely. Perhaps one way to determine proper usage is to think of to affect as meaning to bring about partial results; to effect as meaning to achieve complete results. 'The cost of the farm program affects all our pocketbooks'; 'Arbitration was necessary to effect a settlement of the strike.'

    "There is, of course, another meaning to the verb affect: to pretend or feign something in order to influence: 'She affected a passion for sports because she loved college weekends.'

    "Effect is the only one of these words in common use as a noun; affect (noun) is used only in psychology."
    (William and Mary Morris, Harper Dictionary of Contemporary Usage. Harper & Row, 1975)

  • "Exhortations in Guardian Style have had little effect on the number of mistakes; the level of mistakes has been little affected by our exhortations; we hope to effect a change in this."
    (David Marsh and Amelia Hodsdon, Guardian Style. Guardian Books, 2010)

  • "I assume writers and editors, in a bit of language laziness, have given up on trying to use the words affect and effect correctly, in favor of accepting the word impact as a substitute for both, thus diluting the previous meaning of impact.

    'Good point. What people want to mean when they use impact as a verb (a usage that many revile) might be better expressed by the verb affect: A affects B. The noun similar in meaning to the noun impact is effect: A has an effect on B. A mnemonic might be: The action is affect; the end result is effect."
    (Barbara Wallraff, Word Court. Harcourt, 2000)


(a) Scientists continue to study the _____ of sweeteners on humans.

(b) Controversies over sweeteners have not seriously _____ the sales of diet soft drinks.

(c) Low lying clouds have a cooling _____ on the atmosphere.

(d) Divorce _____ children as well as adults.

(e) "It is time to _____ a revolution in female manners." (Mary Wollstonecraft)

Answers to Practice Exercises

Glossary of Usage: Index of Commonly Confused Words

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