Affect and effect sound almost the same, look almost the same and are both about change. No wonder they cause so many mistakes. The good news is that one short rule gets you the right answer almost every time.
Why they get mixed up
Part of the problem is sound. In ordinary speech, most people say the two words in almost exactly the same way, so you can’t rely on your ear. The other problem is meaning: both words are about one thing changing another, so either seems to fit at first glance. That is why a rule based on grammar, rather than on sound or meaning, works best.
The quick rule
In everyday writing:
- Affect is usually a verb. It means to influence or change something.
- Effect is usually a noun. It means the result of a change.
So something affects you, and the result is an effect.
- The weather can affect your mood.
- The weather can have an effect on your mood.
Both sentences say the same thing. The first uses the verb, the second uses the noun.
A memory trick
Many people use the word RAVEN: Remember, Affect is a Verb, Effect is a Noun.
Another way to remember it: affect comes first in the alphabet, just as an action comes before its result, the effect.
How to check your sentence
If you are not sure which one you need, try these two tests.
1. Look for “the”, “an” or “a”. If one of these comes right before the word, you almost always need the noun: an effect, the effect, a side effect.
2. Swap in another word. Try replacing your word with “influence” (a verb) or “result” (a noun). If “influence” fits, use affect. If “result” fits, use effect.
- The noise didn’t [influence] my sleep → The noise didn’t affect my sleep.
- The [result] of the noise was a bad night → The effect of the noise was a bad night.
The tricky exceptions
The rule above covers almost everything you will write. But there are two exceptions worth knowing, mostly so they don’t confuse you when you meet them.
Effect as a verb. “To effect” means to make something happen or bring it about. It is common in formal or business writing.
- The new manager wants to effect change. (She wants to make change happen.)
- The new manager wants to affect change. (She wants to influence change that is already happening.)
Those two sentences mean different things, which is exactly why this exception matters. If you mean “make happen”, it’s effect. In most everyday sentences, though, you will want affect.
Affect as a noun. In psychology, “affect” (stressed on the first syllable) refers to the emotion a person shows outwardly, for example through their face or voice. A doctor might write that a patient had a “flat affect”. You are unlikely to need this outside medical or academic writing.
Related words
The same pattern runs through other forms of the words.
- Affected describes something that has been influenced: the affected areas. It can also mean artificial or put on: an affected accent.
- Effective means producing the result you want: an effective plan.
- Effects can also mean belongings, as in “personal effects”.
Quick practice
Choose affect or effect. The answers are below.
- Lack of sleep can ___ your concentration.
- The medicine had no ___ on my headache.
- How will the new rules ___ small businesses?
- The special ___ in the film were amazing.
Answers: 1. affect 2. effect 3. affect 4. effects
The takeaway
When in doubt, remember that affect is the action and effect is the result. Check for “the” or “an”, or swap in “influence” and “result”. That will get you the right word almost every time.