Inside the Numbers: Consistency in the Pac-10

Running the ball. Passing the ball. Stopping the pass. Stopping the run. Excel at all four of those fundamentals of football and your team is in the national title game. Excel at three and you're competing for a conference crown, and excel at just one – as Stanford did last year – and you're still just a little luck away from a winning season...

The beauty and agony of college football, however, is that the sport's gods mercilessly hit the reset button each January. No other sport comes close to suffering the turnover common on a college campus. Imagine if every NBA team had to replace two starters and their sixth man every offseason, or if NFL squads regularly lost four offensive linemen each spring. Simply impossible.

As such, discovering which of a team's traits carry over from one season to the next is uniquely important in college football, since the roster is changing so quickly. Stanford fans might be assuming this year's run game will be every bit as strong as last season's, yet hoping that the pass defense shores up and the pass attack takes a major turn for the better. Just how realistic are those hopes?

Here at The Bootleg, we used, as we have in past "Inside the Numbers," statistics from every Pac-10 team since 2002. While our previous pieces, however, were looking at win totals – how experience affects them and how they're likely to fluctuate (or not) from one season to the next – this piece takes for granted that rushing and passing offense and defense affect a team's final record, as any Pop Warner kid worth his chinstrap knows. Thus, we honed in on four stats: rushing yards, rushing yards allowed, passing yards and passing yards allowed. Our objective: to see how much each of these vary between seasons.

I would expect defending the run to be the most consistent between seasons, with defending the pass second, rushing third and passing efficiency the least consistent from one season to the next. My rationale comes from looking at any one individual's effect in each of those areas, the intuition being that while one star quarterback may graduate any given season, it's less likely the entire front seven will. Indeed, lose a quarterback or a star receiver, and your passing game starts virtually from scratch next September. Lose a tailback and your rushing game may be in trouble, but the five offensive line starters will factor in heavily too.

Defense is more of a team effort, plus, unlike on offense, teams can't switch from a 60-40 run/pass balance to a 40-60 balance in an offseason, so I'd expect the defensive numbers to be more consistent between seasons. Still, a cornerback on an island would seem to have more influence on the D's success than any one defensive lineman or linebacker, so I'd expect rush defense to be the most consistent component from one season to the next. If true, this finding would mesh nicely with the conventional wisdom that a program's ability to stuff the run is most telling of its essential toughness and character, qualities that, presumably, are reasonably consistent from one year to the next. (What exactly does an announcer mean when he talks about a team's character anyways?)

I am prepared to be horrifically wrong though, so let's defer to seven years of Pac-10 history and see what the numbers suggest.

Passing yardage:
Average: 242 yards
Average change per team between seasons: 46 yards

Rushing yardage:
Average: 141 yards
Average change: 39 yards

Passing yardage allowed:
Average: 232 yards
Average change: 37 yards

Rushing yardage allowed:
Average: 133 yards
Average change: 33 yards

Sure enough, rushing is more stable than passing and defense more stable than offense, though the differences are slight and our hypotheses don't look so brilliant on a percentage basis. (Offensive and defensive averages aren't identical because non-conference games are included.) Since we have the numbers, let's also examine teams' averages in each of those four categories over the past seven years:

Rushing yards allowed, 2002-2008
1. USC 88
2. Oregon State 102
3. Cal 123
4. Oregon 126
5. Arizona State 133
6. Washington State 141
7. Arizona 149
8. UCLA 151
9. Stanford 158
10. Washington 163

Passing yards allowed, 2002-2008
1. USC 205
2. UCLA 216
3. Oregon State 220
4. Arizona 229
5. Cal 237
6. Arizona State 239
7. Oregon 241
8. Washington 242
9. Washington State 243
10. Stanford 250

Rushing yards, 2002-2008
1. Oregon 184
2. Cal 183
3. USC 179
4. UCLA 133
5. Oregon State 133
6. Washington State 132
7. Washington 126
8. Arizona State 124
9. Stanford 111
10. Arizona 104

Passing yards, 2002-2008
1. USC 279
2. Arizona State 278
3. Oregon State 269
4. Washington State 258
5. Oregon 241
6. Cal 232
7. Arizona 228
8. Washington 226
9. UCLA 216
10. Stanford 195

Several takeaways from this. First, couldn't we be higher than ninth in one of these categories? In fact, in just one of the past seven seasons has Stanford topped the league-wide average in each of those categories: 2002 for passing and rush defense, last season for rushing and 2006, ironically, for pass defense, largely because teams weren't bothering to throw when they could rush for 250 in a game and were ahead by three touchdowns anyways.

Second, rush defense really is the most important stat in the game, as no school differs by more than two spots in those standings and the combined Pac-10 standings over the same time period. If you don't believe me, scan through each of the four above standings, and rush yardage allowed clearly looks most like the standings we've been seeing in each Monday morning's Chronicle these past seven years.

Third, my goodness is USC's defense good – better than 10 yards ahead of the field in both categories. And, finally, these numbers and averages allow us to better put a game or a season in its proper context. Stanford averaging 200 rushing yards and 152 passing yards last season? As great and as horrific as we'd thought, respectively. 135 rushing yards and 235 passing yards per game are the benchmarks – here's hoping Stanford can clear them on both sides of the ball come autumn.

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