Affect vs Effect

"Affect" or "Effect". What's the Difference?

Affect and Effect are different parts of speech, but they sound almost identical. "Affect" or "Effect" are two words that are often confused. They are pronounced similarly and both refer to change. 
However, they have different grammatical roles; one is a verb, and the other is a noun. 

Affect is a verb that describes the act of producing a change in someone or something. 
Effect is a noun that refers to the result or change itself, as in the phrase "cause and effect." 

Sound-alike pairs like affect vs. effect are tricky because many people pronounce them as homophones, which means, well, that they sound alike.

Affect:

Affect means to influence or to produce a change in something. 
Use affect as the verb in a sentence when talking about producing change or making a difference. 

Examples: Affect in a sentence: 

Keeping up late tonight might affect your performance tomorrow. 
The result of the exam will affect your overall grade. 
The independent variable affects the dependent variable.

Tip

If you’re unsure whether you’re using affect correctly, substitute it with another verb (e.g., transform, modify, change).
If the sentence still makes sense, affect is the correct word to use.
If not, you probably mean effect.

Effect:

Effect is a noun, and it means the result of a change. So, if an event affects your life, you will feel the event’s effect. 
An effect is a noun, and it is the outcome of an event or situation that creates a change. The effect of the change can be big or small, but the fact that something changed is what makes the noun form of effect so important. 

Examples: Effect in a sentence: 

Tourism has had a positive effect on the economy. 
The fog created an eerie effect. 
The drug’s side effects are unknown.

Tip

If you’re unsure whether you’re using effect correctly, substitute it with another noun (e.g., outcome, result, consequence).
If the sentence still makes sense, effect is the correct word to use.
If not, you probably mean affect.

How to Remember the Difference Between "Affect" and "Effect" 

The "the word RAVEN" tip helps you use the right words in most situations: 

R = Remember
A = Affect is a
V = Verb
E = Effect is a
N = Noun

Here is another way to remember when to use affect and effect: 
A is for action (affect); E is for the end result (effect).