I ran into this problem several times in the last set of student papers, so it’s time for another illustration. When you’re talking about making a change, you mean the verb “affect,” and when you’re talking about something that results from a cause, you mean the noun “effect.” It’s rare to encounter “effect” as a verb (meaning “bring about”) and even rarer to encounter “affect” as a noun (used in psychology to refer to an emotional response).