Countless writing guides have addressed the erroneous interchanging of affect and effect. We know better, yet it remains one of those usage items that many of us still have to consciously check every time.
In their most common uses, affect and effect have these definitions:
affect: v. to act upon or influence
effect: n. a result
It's easy to see how these words are confused; often they can both be used correctly in the context of a single incident, story, or paragraph:
The thunderstorm did not affect our electrical power, which remained constant through the night. However, the effect of the storm bordered on disastrous in Chicago.
Here's one trick that can be helpful: the e's have it. The word the often precedes a noun. In this case, you get two e's in a row when the right word, the noun, is chosen:
Incorrect: the affect
Correct: the effect
There is a complication. Effect also has a second, less common definition, one that makes it a verb which is almost opposite in meaning from the verb above:
effect: v. to cause
Ex: We'll have to completely overhaul our sales strategy if we expect to effect a change in our bottom line.
Most of the time, this second usage is uncommon enough to disregard. On those rare occasions when the verb form of effect is used, it's worth taking a quick look in the dictionary to verify rather than trying to memorize another rule.
© 2008 by AnnaLisa Michalski