It's obvious by now that quarterback rating is a flawed statistic. The poor statistic has been battered around a bit in the media and with good reason. With the changes to the passing game today it's pretty hard to see the value in a rating without any context. Oh sure, Tom Brady led the league with 111 passer rating this season, but is that historically good? Just alright? It's hard to tell.

Well, that's why I borrowed a concept from baseball and compared quarterback ratings to league average. In baseball the term ERA+ is thrown around a lot for pitchers, but it's basically a park adjusted ERA against league average. Well, in football there is no need for stadium adjustments - at least as far as we know right now - and thus we can just divide Quarterback Rating by League Average Quarterback Rating and a get a number that allows us to more accurately measure passers across seasons.

For instance, Brady's 111 rating was done in the context of an NFL season where the average passer rating for the entire league was 82.2, which is pretty high. Therefore his QB Rating+ would be (111/82.2*100) or 135.0. It turns out that's pretty good.

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