Parity in the NFL…Why you shouldn’t sleep on the Eagles next year

Let’s step away from the draft and free agency for a moment, since we’ve reached a lull in the action there.  Instead, let’s talk about expectations in general, specifically how team performance this past season should factor into our predictions for next year.

I’ve noticed quite a few people are “down” on the Eagles for this coming season.  Nevermind that the draft has yet to happen and free agency is not yet finalized; generally people do not believe the Eagles can be a playoff team next year.  This shouldn’t come as news to anyone, but the real question is why?

I believe the answer is composed of two related parts: A) anchoring, and B) misunderstanding of the overall NFL competitive landscape.


Anchoring is a fairly common problem than many people don’t fully appreciate.  It’s a specific type of cognitive bias that results in poor evaluations/predictions from almost all of us.  Basically, it’s relying too heavily on the first piece of evidence.  A common example is any game that involves guessing how many pieces of something are in a jar (candy usually).  If the guesses are public, then the overall range of guesses will usually center around the first person’s guess.  Despite the fact that everyone is looking at the same jar (has the same info), the initial guess, by virtue of being first, tends to “anchor” all subsequent guesses, regardless of its accuracy.

While football records are obviously a bit different, I submit that the most recent season’s record fulfills a similar function as the first guess in the example above.  Jumping to the Eagles: last season the team won just 4 games.  Consequently, predictions for next season  are all made in reference to that number (which is why predicting the playoffs for the Eagles next year isn’t common).

Despite the fact that last year’s team roster/scheme/coaching staff/etc… bears little resemblance to the one the Eagles will play next season with, the record remains a major factor.

So the obvious question for us is: how useful is last season’s record in predicting this coming season’s?

Taking the last ten seasons for each team, I plotted season records against the same team’s record from the following year.  Here’s the chart:Screen Shot 2013-03-25 at 12.09.17 PM


There definitely appears to be correlation (as we’d expect), but the value is just .30 (weak/moderate).  Additionally, I’d argue that within this sample are two teams that have an inordinately large impact on the overall correlation values by virtue of their remarkable consistency (the Patriots and Colts obviously).  While I’m usually hesitant to play with the sample, in this case I think it’s worth looking at the results without these teams.  In essence, due mainly to the Brady/Manning effect, I think they are anomalous and a poor representation of the usual state of the league.  More specifically, I think they are useless when it comes to drawing conclusions about the Eagles this year.

When we remove them, the correlation value drops to .22.  Still real but fairly weak.

So far, we’ve got reasonable evidence that the Eagles record this year doesn’t mean much when it comes to next year’s performance.  I’d actually argue that it has almost NO SIGNIFICANCE, due to the overall weak correlation combined with the dramatic makeover the team has undergone.

Average Change

We can also look at the average change in record from year to year.  Using the same sample, I found the absolute value of the difference in wins from one season to the next.

The verdict?  On average, NFL team’s # of wins change by 3.07.  With just 16 games in a season, a 3 win difference in either direction is BIG.  Also, that’s AVERAGE, which means there were a LOT of changes greater than 3.

In fact, the median value was 3, which means half of the season-to-season changes were GREATER than 3 wins/losses.


This obviously has large implications for the Eagles, and more specifically Eagles fans.  A change of 4 wins (slightly above average) puts the Eagles in playoff contention (or a winless season).

To be clear: All fans are free to COMPLETELY IGNORE last season’s record, for it is a very weak indicator for how the team will perform this coming year.

At the moment, I’m fairly bullish on the Eagles chances for next year, though there is still a long way to go.  In any case, the fact that the team sucked last year really doesn’t matter, so by all means, forget it ever happened.

P.S. you’re welcome.


2 thoughts on “Parity in the NFL…Why you shouldn’t sleep on the Eagles next year

  1. Well done. I am seriously thinking about putting money on the Eagles over/under for wins this coming season. And I have never bet on pro sports in my life.

  2. I feel the same way but I kind of like that hopes aren’t as high as usual for the Eagles next season. Less external pressure might be good for this team. I’m sure Chip will put enough internal pressure on each player to play at a high level and hopefully we will be pleasantly surprised by the team’s performance.

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