AAAA-ffect or EEEE-ffect

Notice the difference in these two sentences:

1. Changing the way you add will not affect the score.

2. Changing the way you add will not effect the score.

Sentence 1 means that changing the way you add will not cause the score to change. Sentence 2 means changing the way you add will not get you a new score. There is a subtle, but important, difference.

Affect and Effect are often confused because both can be used as a noun or as a verb. Whereas effect means bring about, cause to happen, or produce a result, affect means have an influence on, or produce an effect, as in

These rules affect the teachers, but they don't affect me.

Compare this to

The right medicine can effect a quick change in your health.

NOTE:In psychology, "affect" has the special meaning of attitude, as in "The student's affect is an important factor in his or her success."