These two words often cause grammar ailments, and curing the problem can admittedly be a bit tricky. It all comes down to how the word is functioning in your sentence: Is the word a verb? If so, you’ll typically use Affect. On the other hand, if the word is a noun, you’ll use Effect.
Affect is a verb meaning to produce a change. Use it to suggest how one thing changes another:
Unseasonably warm winters affect the ecosystem.
Affect is a verb that also means to influence feelings or emotions. Use it to explain that something made you feel a certain way:
The melancholy opera affected me tremendously, and I was depressed afterward.
So if the word is doing something (i.e. if it is an action word also known as a verb), use Affect.
Conversely, if the word is functioning as a noun, use Effect.
Effect is usually a noun that means the result, outcome, or consequence. Use it to describe how something turned out:
The worst effect of the medicine was severe drowsiness.
The team partied the night before the big game, and the effect was that they were too tired to play.
Effect is also a noun that means the power to produce results. Use it to say whether or not something was able to happen:
The labor union’s strike had a minuscule effect on salary negotiations.
My suggestions had no effect on her decision.
Here’s a useful trick for remembering this usage: If the word is preceded by an article (the, a, an), you will use Effect—always (Notice the bold articles in the previous examples). Why? Because articles always precede nouns. Sometimes there will be an adjective in between the article and its noun, but articles always precede nouns. Thus, you would never say The
Affects of the medicine were severe or An Affect of the medicine was . . .
So here’s the bottom line: If it’s a verb, you’ll typically use Affect. If it’s a noun, use Effect.
Need a higher dose of word choice tips? Check out these other word battles: