An explanation of RIPPEN

Alex Smith led the way in quarterback performances this week with an astonishing RIPPEN just over 43, and Blaine Gabbert continues to dwell at the bottom of all of my tables with a RIPPEN just above 3.

RIPPEN rankings for week 5 performances:

Looking at RIPPEN based on the whole season, Tom Brady is ranked number 1 with a RIPPEN of 27.304, which is essentially the same as RGIII’s RIPPEN of 27.279.  The top five is rounded out by Payton Manning, Alex Smith, and Matt Ryan.  My RIPPEN top five is the exact same top five as sorted by season QB rating, but in a different order.  QB rating has the top five guys ranked Smith, Ryan, Brady, Manning, RGIII.

The bottom five according to RIPPEN are Weeden, Kolb, Cassel, Gabbert, and, dead last, Matt Hasselbeck.  QB rating has three of these quarterbacks in the bottom five (Weeden, Cassel, and Gabbert), but by QB rating Sanchez and Tannehill are also in the bottom five.  I have Tannehill 19th and Sanchez 25th out of 32 quarterbacks.

As for most over and under rated quarterbacks, I regressed QB rating as a function of RIPPEN and, as expected, they are highly related.  (QB rating is approximately 58 + 1.63*RIPPEN).  However, there are some large deviations.  The most under-rated quarterback based on QB rating is Cam Newton.  His QB rating is only 80.9, but, based on RIPPEN, we’d expect him to have a QB rating about 16 points higher around 97.  Other under-rated quarterbacks include Ryan Tannehill who is about 14 points lower than expected and Mark Sanchez who is about 11 points lower than expected.  (But don’t get me wrong here, I still think Sanchez is a terrible quarterback.  I just don’t think he is the 30th best quarterback in the league, I think he’s 25th.)

The most over-rated QB based on passer rating is Kevin Kolb.  Based on his passer rating, he is ranked 16th among quarterbacks, but RIPPEN has him ranking 29th.  Based on his RIPPEN, his expected QB rating is 75.3 about 14 points lower than it actually is.  This is likely do to the weight that passer rating gives to touchdown passes.  The next two most over-rated QB’s are Ben Roethlisberger and Eli Manning.  Roethlisberger has a QB rating about 11 points higher than we would expect and Manning is about 10 points higher than expected.

Season RIPPEN rankings through five weeks of games:

And finally, below is a plot of estimated outcome percentages that are used in calculating RIPPEN.  If you look at Peyton Manning in the upper right corner of the plot you can see that starting from his own 20 yard line and only throwing passes in a simulated world, hell score a touchdown about 32% of the time and convert a field goal about 16% of the time.  So he’d score on around 48% of drives. Compare this with Blaine Gabbert who will score a touchdown on about 6% of drives and get a filed goal about 9% of drives.  This means that 85% of Gabbert drives, in the simulated RIPPEN world, end in either a punt, an interception, or a missed field goal.

Cheers.