A Double-Sided Error

Short post today, since we have actual, non-Eagles football to care about and discuss.

Everyone's had a chance to speak his piece on the McNabb issue in Friday's thread.  Ideally we can all just stand on our previous statements and not re-hash the whole thing every time there's a new post mentioning McNabb.  A lot of good points were made on both sides, although personally I find the trade value / cap issue lines of attack much more convincing than the "McNabb sucks" arguments.

There was one issue that came up a bunch in the thread that I want to discuss, however.  There's a mistake being made by (some) partisans on both sides, and it goes something like this:

Version #1 -- If we trade McNabb, we're basically blowing up the QB position for a year, so while it might make sense over the long run, we know for a fact we're going to miss the playoffs next year and cost ourselves a shot at a ring while we rebuild.

Version #2 -- We have no way of knowing how good Kolb will be, but after 11 years of McNabb, and especially given his performance the last few years, we know for a fact he's just not good / consistent / special enough to win us a Super Bowl.

The same mistakes are being made on both sides here.  First of all, there's just way too much certainty being expressed.  If results were actually this knowable this far in advance, we could stop wasting time arguing about things like this and just go put our life savings down on next year's over/under for Eagles wins.

That's not to say we can't make some predictions with a reasonable level of certainty.  Kolb probably would throw more interceptions than McNabb over a 16-game season.  He'd also probably complete fewer deep balls, but be much more efficient on passes under 10 yards.  All of these things seem pretty likely given the histories of both men.

The unknowable part, though, comes in trying to understand how all that will balance out.  Maybe the lack of a deep passing threat means opponents will jam the line, blitz the heck out of us and render our running attack even more impotent.  Or maybe Kolb's ability to complete short passes in tight windows backs off the blitz after a couple big catch-and-runs.  We just don't know.

(He might even throw a pick on the last offensive play of the season.  Again.  Boy, that would suck.)

The second issue is one of variance and team effects.  Look at how much year-to-year fluctuation there is over time for a number of long-career QBs: Favre, Brady, Warner, Brees, Garcia, Hasselbeck, Young, Montana, McNair and even Brad Johnson.  It's not uncommon to jump 10-15 points from one season to the next.

If you accept that the Eagles did have some issues this year -- WR turnover, offensive line problems and no running game -- it's really not that big a leap to think McNabb's performance could take a huge step forward next year if those issues were addressed.

Or maybe it wouldn't.  Only one way to find out, though.