Oversigning meets yppd

So, I can’t help my love for yppd (yards per per play differential).  I think it’s a great indicator of relative team strength.  I thought it would be interesting to compare a team’s yppd vs the size of their classes – so does oversigning help or hurt a team’s performance?

On the one hand, the data is clearly all over the place.  There are bad teams that sign a lot of players and there are good teams that sign a lot of players. 

That said, check this out – here are yppd scores (x-axis) mapped against the 4-year average size signing class (y-axis, using data from oversigning.com).  This is data for BCS schools only for 2006-2011 seasons.  The dots are specific “YPPD scores” (actual yppd + a SOS adjustment), the red line is a 5 data-point rolling average.

Interestingly, there is a very straight line here – the better the team is from a yppd perspective, the more players they sign on year on average.   Although, it trends up by only about 1.5 signees/yr (23 is at 0 yppd score [average] and about 24.5 as you move towards the top end).  

Also interestingly, is how, for the most part, top teams sign a high number of players.  Consider the list below – showing all teams with a 2 or greater yppd score – and how large their signing classes are.

So, the intuition that oversigning helps teams looks to be true, at least at a high level.



(the teams below are the top 27 yppd teams & avg # of signees over a 4 year period... the average class size is 24.7, the average class size of the bottom 27 is 22.8)
2006 West Virginia  29
2011 Alabama  28
2009 Alabama  28
2010 Auburn  28
2010 Arkansas  28
2010 Alabama  27
2007 Texas Tech  27
2011 LSU  26
2006 Arkansas  26
2008 Oregon  26
2011 Oregon  25
2010 Oregon  25
2007 Oklahoma  24
2007 West Virginia  24
2006 Texas Tech  24
2007 Mizzu  24
2008 Florida  24
2009 Florida  24
2007 Florida  24
2008 Oklahoma  24
2006 LSU  23
2007 LSU  23
2007 USC  23
2006 Florida  23
2011 Wisconsin  22
2009 Texas  21
2007 Ohio State  20