Affect and Effect: One Trick Covers Ninety Percent of Cases
Affect is usually a verb meaning “to influence”. Effect is usually a noun meaning “a result”. So the noise affects your sleep, and lack of sleep has an effect on your mood. That one rule settles most sentences; the rest of this page covers the quick tests, the two real exceptions, and the phrases where people slip.
The rule that covers most of it
- Affect is a verb. It means to influence or change something. The delay affected the schedule.
- Effect is a noun. It means a result or consequence. The delay had an effect on the schedule.
The memory hook: Affect is an Action. Effect is an End result. Some people also use “RAVEN”: Remember, Affect is a Verb, Effect is a Noun.
Three quick tests
- The article test. Put the or an in front of the word. It had an ___ on morale – “an” fits, so you need a noun: effect. It will ___ morale – “an” makes no sense, so you need a verb: affect.
- The substitution test. If influence or change fits, use affect. If result fits, use effect.
- The adjective test. Words like positive, negative, lasting, side or special describe nouns, so they come before effect: a positive effect, special effects. Adverbs like badly, deeply or directly go with the verb affect: badly affected.
Every form in one table
| Form | Part of speech | Example |
|---|---|---|
| affect / affects | verb, present | Stress affects everyone differently. |
| affected | verb, past / passive | The flood affected 200 homes. Thousands were affected. |
| affecting | verb, -ing form | The issue is affecting sales. |
| effect / effects | noun | The medicine has few side effects. |
| effective | adjective (from the noun) | an effective treatment; effective immediately |
| affective | adjective (psychology) | affective disorders (disorders of mood) |
| effected | verb, past (rare: “brought about”) | The new director effected major reforms. |
“Affects” and “effects” sound almost the same in quick speech, which is why the spelling mistake is so common. Run the article test on the plural too: the effects of the storm (noun), the storm affects travel (verb).
The two exceptions
Both are real, both are less common than the rule, and both are exactly where confident writers slip.
Effect as a verb means to bring about, to cause to happen. It is formal and lives mostly in the phrase to effect change.
- The new manager effected several changes. She made them happen.
- The new manager affected several changes. She influenced changes that were already under way.
Both sentences are grammatical and they mean different things. If you are not sure which you mean, you almost certainly mean affect; “effect” as a verb almost always has change, reform, a transfer or a cure as its object.
Affect as a noun is a psychology term for a person’s visible emotional expression – how their mood shows in their face, voice and posture. The patient presented with flat affect. The stress moves to the first syllable: AF-fect. You will rarely need it outside clinical, nursing or psychology writing; if you do, see our list of words to describe affect (flat, blunted, labile, congruent and more).
Two more meanings worth knowing
- affect = to pretend or put on. He affected an English accent. She affected indifference, but she was clearly hurt. From this comes the adjective affected, meaning unnatural or showy: an affected laugh.
- effects = belongings. In formal or legal English, personal effects are the things a person owns or carries: The hospital returned his personal effects.
The phrases people get wrong
| Phrase | Correct form | Why |
|---|---|---|
| in effect | The rule is in effect. | noun (“in operation”) |
| take effect | The changes take effect on Monday. | noun |
| come into effect | The law comes into effect in May. | noun |
| side effects | Possible side effects include headaches. | noun, always |
| to that effect | He said something to that effect. | noun (“with that meaning”) |
| for effect | She paused for effect. | noun |
| to effect change | Voters want to effect real change. | the verb exception |
| affected by | Areas affected by the storm | verb, passive |
| the effect on / the effect of | the effect of sugar on teeth | noun + preposition (not “the affect on”) |
The one that trips everybody
The changes will effect the department and the changes will affect the department are both grammatical. The first says the changes will bring the department into being. The second says they will influence it. Nine times in ten you mean the second. Ask whether the thing already exists: if it does, you are influencing it, so use affect.
The escape route
If you are genuinely stuck, rewrite around it. The delay changed the schedule. The delay had consequences for the schedule. The delay disrupted the schedule. Each is more specific than either original, which is usually a sign the rewrite was the right move anyway. (“Impact” is another common substitute, as a noun or a verb, though some editors prefer to keep it for strong, physical effects.)
Practice: affect or effect?
- The cold weather didn’t ______ the match.
- The new rules come into ______ next week.
- What ______ did the news have on you?
- Thousands of commuters were ______ by the strike.
- The coach wants to ______ a change in the team’s attitude.
- Caffeine ______ people in different ways.
- The film’s special ______ were impressive.
- The drug can have serious side ______.
- He spoke with a slightly ______ accent that his friends found annoying.
- Her speech had a powerful ______ on the audience.
Answers: 1. affect. 2. effect. 3. effect. 4. affected. 5. effect (to bring about a change). 6. affects. 7. effects. 8. effects. 9. affected (= put on, not natural). 10. effect.
Quick answers
Is it “affect” or “effect” on someone? “It had an effect on me” (noun) or “it affected me” (verb). Never “an affect on me” in everyday English.
Is it “effected” or “affected” by? Almost always “affected by”: people affected by the closure.
What is the difference between effective and affective? Effective means it works or produces a result. Affective is a psychology word meaning “to do with emotions or mood”.
For more pairs like this, see our commonly confused word pairs, plus imply vs infer and continual vs continuous.
Checked against Merriam-Webster, the Chicago Manual of Style and the AP Stylebook. Spotted an error? Tell us — see our editorial policy.
