Affect vs. Effect: How to Pick the Right Word Every Time

Affect is usually a verb that means “to influence or change something.” Effect is usually a noun that means “the result of a change.” If you can put the or an in front of it, you almost certainly want effect.

• The cold weather affected my mood. (verb: it did something)
• The cold weather had an effect on my mood. (noun: the result)

That one rule handles the vast majority of sentences you will ever write. This GrammarVista.com USA guide also covers the two exceptions, the phrases that cause the most second-guessing, and a short practice set so the rule sticks.

The Default Rule: Affect Is a Verb, Effect Is a Noun

Think of it as cause and result. Affect is the cause in action. Effect is what you see afterward.

A few more pairs show the pattern:

• Caffeine affects sleep. / Caffeine has an effect on sleep.
• How will the new policy affect remote workers? / What effect will the new policy have on remote workers?
• The noise didn’t affect her concentration. / The noise had no effect on her concentration.

Notice the giveaway words around effect: an effect, the effect, no effect, side effects. Articles and adjectives attach to nouns, so they point you straight to effect. The Touro University Writing Center gives the same tip: effect often follows words like the, an, into, and take.

Quick rule: If the word follows a, an, the, or an adjective, use effect. If it describes what something does to something else, use affect.

Memory Tricks That Actually Work

RAVEN

The most popular trick is the acronym RAVEN: Remember, Affect is a Verb, Effect is a Noun.

A Comes Before E

In the alphabet, A comes before E. In real life, an action (affect) comes before its result (effect). You affect something first; the effect shows up later.

The Arrow Test

Picture affect as an arrow pointing at something: The storm → affected → the flight. If your sentence has that shape, with something acting on something else, affect fits.

Exception 1: “Effect” as a Verb

As a verb, effect means “to bring about” or “to cause something to happen.” It usually appears with words like change, reform, or a cure.

• The new manager effected real change in the department. (She brought about change.)
• Activists worked for years to effect reform.

Compare these two sentences, because the difference matters:

In almost every case, writers mean the second one. If you’re tempted to write “affect change,” ask whether you mean “bring about change.” If so, use effect.

Verb effect is fairly formal, though. In everyday writing, “made changes” or “brought about change” often sounds more natural.

Exception 2: “Affect” as a Noun

In psychology and medicine, affect (stressed on the first syllable: AF-fect) means a person’s observable emotional expression, such as facial expressions, tone, and body language.

• The patient showed a flat affect during the interview.
• Her affect brightened when her family arrived.

Unless you’re writing a clinical report or a psychology paper, you will rarely need noun affect. If you’re writing about results or outcomes, the noun you want is effect.

A Bonus Meaning: “Affect” as “To Pretend”

Affect can also mean to put on a manner that isn’t natural to you. That’s where the adjective affected (“artificial” or “showy”) comes from: He affected a British accent after one semester abroad.

Tricky Phrases: Which Spelling Do They Use?

Some fixed phrases cause trouble because they don’t match the cause-and-result idea at first glance.

“Affected By” vs. “Effected By”

“Affected by” is the one you want almost every time: Thousands of residents were affected by the flooding.

“Effected by” is correct only when you mean “brought about by”: The merger was effected by a team of lawyers. That’s rare. When in doubt, choose affected by.

Affect and Effect in Different Forms

The rule still applies when the words change shape.

• Affecting (adjective): The song was deeply affecting. (It moved people.)
• Effective (adjective from effect): The new filter is very effective. (It produces results.)
• Unaffected (adjective): The rural roads were unaffected by the snow.

Affective is a real word, but it’s another psychology term meaning “related to emotions,” as in affective disorders. A solution that works is effective.

The Hamilton College Writing Center lists affect/effect among the word pairs writers most often confuse. For the full set, see our guide to commonly confused words or browse the Tricky Words section.

Practice: Affect or Effect?

Try this short GrammarVista.com USA practice set. Fill in each blank with affect, affected, effect, or effects.

1. The medication has a few mild side ______.
2. Bad weather can ______ your flight schedule.
3. The new speed limit takes ______ on January 1.
4. Everyone in the office was ______ by the power outage.
5. The committee hopes to ______ lasting change in the school system.
6. Lack of sleep had a noticeable ______ on his performance.

Answer Key

1. effects (noun: results of the medication)
2. affect (verb: weather influences the schedule)
3. effect (fixed phrase: “takes effect”)
4. affected (verb: the outage acted on everyone)
5. effect (verb meaning “bring about”)
6. effect (noun, after “a noticeable”)

If you got number 5, you’ve mastered the hardest part. Knowing verbs from nouns is what makes this pair easy, so the Grammar Rules section is a good next stop. You can also try who vs. whom.

The Bottom Line

In everyday American English, affect is the verb and effect is the noun. Watch for the two exceptions, effect change and the psychology noun affect, and remember take effect, in effect, and affected by.

Apostrophes cause a similar mix-up, and our post on its vs. it’s fixes it with a one-second test. After that, the American punctuation rules guide covers commas, quotation marks, and more.

For more quick, practical fixes like this one, explore GrammarVista.com USA.