Via Kotaku, according to a survey from the University of Oregon, Madden football games make players smarter about football:

What does it mean to bring an 8th man into the box? If you’re looking for the correct answer, you’re more likely to receive it from an EA SPORTS Madden NFL player than from someone who doesn’t play Madden. EA SPORTS, a label of Electronic Arts Inc., (NASDAQ: ERTS), announced today the results of a new survey by the University of Oregon’s Warsaw Sports Marketing Center, that determined fans who play the Madden NFL video game series are more knowledgeable about the game of football than people who don’t play the game. The survey found that Madden NFL players’ football IQ was 60 percent higher than people that don’t play Madden.

Emphasis mine.

Fans who play Madden football know more about football in general than fans who don’t play Madden football. The obvious conclusion is that Madden made them smarter, right? Wrong. The correlation here could just as easily be that people who are bigger fans of football are more likely to play Madden than those who aren’t fans. Similarly, the bigger your enthusiasm for football in general is, the more video game football you are likely to play.

Is it possible that Madden somehow educates players in football facts? Yes. Does this study actually lead us to that conclusion? Not from what I read.