I've noticed that some people use effect and affect interchangeably. What are the differences between these two and when are the proper situations to use each of them?

  • 1
    It's interesting that this is tagged as a homophone, since I personally pronounce, affect as /a'fekt/ whereas I pronounce "effect" as /ɪːfekt/. Of course, this varies widely by region. That is, I have a short "ah" sound in "affect", and a long "ee" sound in "effect". Aug 9 '10 at 10:00
  • @Vincent I rolled it back, there should be a better tag for these kind of questions. I couldn't come up with anything interesting. Any ideas?
    – Mysterion
    Aug 9 '10 at 14:20
  • I admit, my pronunciation suffers because I speak too quickly, but for the most part, I've heard "effect" and "affect" pronounced with the same "uh" sound.
    – kitukwfyer
    Aug 9 '10 at 20:47
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    I said it was interesting, not that it was wrong. Homophones very often depend on the accent of the speaker. For instance, on "affect", 99% of people don't use the /a/ sound, but I do. I think homophone is indeed an appropriate tag. Aug 10 '10 at 0:17
  • 3
    Relevant: xkcd.com/326
    – Dan Burton
    May 24 '11 at 21:30

The noun is usually "effect" -- unless in more formal or literary contexts in which case "affect" as a noun can mean feeling or emotion.

The verb is generally "affect", although "effect" is possible if the meaning is "put into place" or "carry out".

Here are some example sentences:

"His plans had no effect on me."

"His disconsolate eyes brought on a sad affect."

"His plans affected me."

"He effected a plan to change the world."

  • 2
    +1 for bringing up affect as a noun, fascinating word, hard to get your mind around what it actually means, like reading Heidegger or something: en.wikipedia.org/wiki/Affect_%28psychology%29 Aug 9 '10 at 15:27
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    Yep, each word can be used as both a noun and a verb and 3 of the 4 uses are related to the same concept, causation. No wonder people get confused: It's confusing! Nov 4 '10 at 15:47
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    "His plans had no effect on me." and "His plans affected me." seem like the same sentence, except for whether or not "me" was impacted. I still don't know what to do. Any more help?
    – Jeff
    Mar 14 '12 at 22:26
  • Jeff - In the first sentence, effect is a noun, in the second sentence, affected is a verb. The sentences effectively have the same meaning.
    – Jay Elston
    Jul 16 '12 at 17:34
  • I was ready to slam the latest edition of the AP Stylebook for going soft on the distinction between "affect" and "effect", but it's not that simple, see arcticllama.com/blog/writing-tips/grammar/…. Unfortunately, most of my colleagues in the corporate world have given up and just use "affect" for every occasion.
    – RobC
    Jan 21 at 19:05

The "common errors" site mentions 3 different meanings for affect (verb):

  • When “affect” is accented on the final syllable (a-FECT), it is usually a verb meaning “have an influence on”:
“The million-dollar donation from the industrialist 
 did not affect my vote against the Clean Air Act.”
  • to make a display of or deliberately cultivate.
    Occasionally a pretentious person is said to affect an artificial air of sophistication.
    Speaking with a borrowed French accent or ostentatiously wearing a large diamond ear stud might be an affectation.

  • emotion.” (when the word is accented on the first syllable (AFF-ect)).
    In this case the word is used mostly by psychiatrists and social scientists—people who normally know how to spell it.

When you affect a situation, you have an effect on it.

Less common is a verb meaning “to create” (to cause to come into being):

“I’m trying to effect a change in the way we purchase widgets.”

The Merriam-Webster details:

The verb effect goes beyond mere influence; it refers to actual achievement of a final result.

  • 1
    Now I think I am even more confused!
    – jp2code
    Jun 14 '11 at 20:03
  • So I think an easy to use rule is: If it is a think (noun) or means 'to create', then use "effect", else use "affect". Anyone comments from the experts out there?
    – Jeff
    Mar 14 '12 at 22:36

The rule that mostly works it this: affect = verb, think "a" for action, wheras effect = noun, the result of the action

to remember: "a" comes before "e" in the alphabet, and you must affect something to cause an effect

  • 2
    Unfortunately, there is both a noun and a verb 'affect' and a noun and a verb 'effect'!
    – jbeldock
    Jan 30 '14 at 7:00

Here’s a quick informal technique for you: If it is not easy for you to remember that that the word “affect” is most commonly used as a verb while “effect” is usually used as a noun, then label this confusion as “aven.” It sounds like amen. The “av” in aven should make you recall affect as verb and the “en” is effect as noun.

Source: A Snappy Guide to Differentiating “Affect” and “Effect”

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