This goof belongs to the venerable news service, Gallup, which just goes to show that sometimes even smartypants make grammatical gaffes.
Where does Gallup go wrong? This headline mistakenly uses the verb "affect" instead of the noun "effect."
- Use affect if it's a verb. Blowing off homework assignments will affect my grades.
- Use effect if it's a noun. The effect on my grades was enormous.
- RAVEN: Remember Affect is a Verb and Effect is a Noun.
- Affect = Action and Effect = End.
Correction: Assessing the Effect of the Afghanistan Documents Leak
Exceptions: Alas, very occasionally "affect" can be a noun and "effect" can be a verb. But if you remember RAVEN, you'll be right 99% of the time.