Saturday, February 10, 2007

Home Field Advantage and Rushing

Using the pro-football-reference.com database, I looked at all teams that finished between 6-10 and 10-6 for the years 1995-2006. Why those records? It's partially arbitrary-- I could have just as easily narrowed it to 9-7/7-9, or expanded it to 11-5/5-11. But my goal was to look at the middle class of the NFL, teams that generally have some strengths but also some flaws. I felt this dividing line would accomplish that.

I then compared some of the standard rate stats, such as rush yards per attempt and pass yards per attempt, to see what team characteristics, if any, contributed to a greater difference between home and road winning percentages. This post will focus on the rushing stats, both offensive and defensive.

210 total teams finished between 6-10 and 10-6 during the 12 seasons reviewed, an average of over 17 per season--so slightly more than half the teams in the league on average. The entire group averaged winning .586 at home and .417 on the road, for a +.169 difference between home and road winning percentages. This would equate to +1.36 more home wins than road wins over the course of a 16 game schedule.

Here are the numbers divided by offensive rush yards per carry:
  • 3.5 and below - 32 teams; .582 at home; .398 away
    3.6 to 3.8 ypc - 34 teams; .590 at home; .408 away
    3.9 to 4.1 ypc - 63 teams; .567 at home; .423 away
    4.2 to 4.4 ypc - 40 teams; .591 at home; .417 away
    4.5 and above - 41 teams; .611 at home; .431 away

Here are the numbers divided by defensive rush yards allowed per carry:

  • 3.5 and below - 26 teams; .611 at home; .399 away
  • 3.6 to 3.8 ypc - 47 teams; .625 at home; .380 away
  • 3.9 to 4.1 ypc - 57 teams; .605 at home; .425 away
  • 4.2 to 4.4 ypc - 41 teams; .537 at home; .419 away
  • 4.5 and above - 39 teams; .548 at home; .460 away

There is basically no indication that simply running the ball better on offense, without any other info, either increases home field advantage or reduces road disadvantage.

Unlike the offensive numbers, the defensive numbers appear to show a difference between how the "middle class" performs at home vs. on the road, depending on whether the team is good at run defense or not. Teams that are not particularly good at stopping the run show less difference in how they perform at home vs. on the road.

If the strength of rush defense does increase home field advantage, there is a potential explanation. If a team is better at stopping the run, it is conceivable that such a team would be somewhat more likely to place its opponent into more 3rd and long situations. This might translate to a bigger advantage at home, where the offense is subject to crowd noise, than on the road, where the home crowd would presumably be quiet to aid the offense. Of course, we also need to keep in mind that this is looking at some of the variables. A team that is poor at stopping the run, yet finishes in the middle, likely has strengths in other areas to compensate. A team that is good at stopping the run, but does not finish in the upper tier, also likely has some other flaws that may be combining to create road disadvantage as well.

Next time, I will play with the passing numbers, overall offensive numbers and overall defensive numbers.

No comments: