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Affect and Effect

The Quick Answer
What is the difference between effect and affect?
  • Effect. Effect is a noun. Effect means outcome, consequence, or appearance.
  • To Affect. To affect is a verb. To affect means to transform or to change.

Affect and Effect

There is often confusion over the words effect and affect. In order to understand which to use, you must know the difference between a noun and a verb.

Effect is a noun. Affect is a verb. (If you're not confident with spotting nouns and verbs, there are some workarounds below to help.)

Effect

Effect is a noun meaning outcome, consequence, or appearance. For example:
  • What effect did your reprimand have?
  • That is a nice effect.

Affect

To affect is a verb meaning to transform or to change. For example:
  • Did the cold affect you?
  • Do not use low-fat milk. It will affect the taste.
Try the Substitution Trick

A Little Trick To Spot Effect

The word effect has several meanings. It can mean outcome, consequence, or appearance. Try using one of these instead of effect. If the sentence still makes sense, then effect is almost certainly correct.

(This trick works because effect is a noun, just like the words outcome, consequence, and appearance.)

A Little Trick To Spot Affect

Try using the verb to transform (in its various forms, e.g., transforming, transformed, transforms) instead of affect. If the sentence still makes sense, then affect is almost certainly correct. However, if you find yourself trying to use transformation, then you should be using effect because both are nouns.

(This trick works because to transform is a verb, just like to affect. )

Example Sentences with Effect and Affect

Here are some example sentences with effect and affect.

Example 1:
  • What effect did foot-and-mouth disease have on your business?
  • (The word effect is a noun.)
Tip: Try substituting the noun effect with the noun consequence to confirm that it's a noun.

Substitution Test: "What consequence did foot-and-mouth disease have on your business?"
(As this sounds okay, effect must be correct.)


Example 2:
  • Did foot-and-mouth disease affect your business?
  • (The word affect is a verb.)
Tip: Try substituting the verb affect with the verb transform to confirm that it's a verb.

Substitution Test: "Did foot-and-mouth disease transform your business?"
(As this sounds okay, affect must be correct.)


Example 3:
  • Do not allow this incident to effect your decision.
Tip: Do the substitution test.

Substitution Test: "Do not allow this incident to consequence your decision."
(As this is nonsense, effect must be wrong.)

The Other Substitution Test: "Do not allow this incident to transform your decision."
(As this sounds okay, affect must be correct.)
  • Do not allow this incident to affect your decision.
Note: Sometimes, the noun-substitution test won't work with consequence because effect is quite a versatile word. You might have to try other nouns, e.g., appearance. If you find yourself trying to use this word as a verb (e.g., appear, appears), then you should be using affect not effect.

Affecting and Affected

There should be no confusion with affecting or affected. These are always verbs (well, nearly always - see the "Beware" section).
Interactive Test
 
 
Top Tip

This Tip Will Work Most of the Time

You almost certainly want effect (not affect) if the word before is an or the.
Beware

It's Not That Simple Unfortunately

Most of this page is dedicated to telling you that effect is a noun and affect is a verb. That is an appropriate start point for learning about the difference between effect and affect, but unfortunately it is not always true. Be aware that effect can be a verb, and affect can be a noun.

The Verb To Effect

Effect as a verb is fairly rare, but it is useful in business writing. It means to bring into being. For example:
  • The new policy will be effected as soon as the paper is signed.

The Noun Affect

The noun affect is extremely rare. It is used in psychology to describe a subjective feeling caused by a thought or other stimulus. It is similar to mood or emotion and carries a connotation of there being external physical signs.  For example:
  • The patient displayed an unusual affect when questioned.