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Yards per point (YPP) is a simple metric to indicate how a team’s total scoring, or scoring allowed, relates to the underlying offensive or defensive yardage. I first picked this stat up from Phil Steele’s annuals, like most of the minuscule bit I think I know about college football.
YPP is simple to compute: If your team has 80 offensive points in the season and has gained 1200 offensive yards, its offensive YPP is 15.0 (1200 / 80). If it’s allowed 100 points and given up 1200 yards, its defensive YPP is 12.0 (1200 / 100).
In one sense you want your offensive YPP to be low, and your defensive YPP to be high. (If this is confusing, recall that points are the denominator of the YPP calculation, so flipping the ratio would mean that points are highest when YPP is lowest.) That indicates your offense is effeciently making the most of its opportunities and the defense is practicing the time-honored philosophy of “bend but don’t break.”
However, a more long-term view suggests that YPPs tend to return to the mean, that it’s unlikely that a team can keep its YPP very high or very low over the course of games and seasons. Therefore, if a high or low YPP is just an artifact of dumb luck and small samples, then we’d expect teams with high offensive YPPs (i.e., offenses that have been really “inefficient”) to improve, and teams with low ones to decline. Likewise, we’d expect teams with high defensive YPPs (i.e., that are keeping their opponent’s offenses from scoring much based on the yardage allowed) to decline, and teams with low defensive YPPs to improve.
Steele indicates that this does indeed happen from year to year (Steele, 2008, p. 299). However, he also notes the following:
- More teams with a low offensive YPP (”efficient” offenses) don’t decline as much as teams with a high OYPP improve. Steele takes this to mean that, “there are some teams like USC that will benefit from turnovers on a yearly basis.”
- Conversely, we might expect teams with a high defensive YPP (”bend but don’t break”) to also decline relatively less often. But in fact Steele finds that this isn’t the case.
I haven’t vetted them yet but here are some interesting-looking articles Google gave me on YPP:
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1 Moving the yardage dicussion forward // Sep 26, 2008 at 1:18 pm
[...] and efficient red-zone performance on both ends — in other words, a team with a low offensive yards-per-point (YPP) and a high defensive YPP — was able to sustain that performance over the course of [...]
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