2018 college football returning production rankings: Clemson’s ready. Who else?

By now, you might be familiar with my process for releasing each season’s S&P+ projections:

Because February’s Signing Day is a little bit later into the month this year (February 7), the recruiting post and overall S&P+ projections post will end up publishing after the series begins on on Monday, Feb. 5.

Over the last few years, I have attempted to move beyond the too-simple “returning starters” figure to measure experience and returning production.

We use the best tools we have, even if they’re not that great. We try to derive value from offensive line starts because it’s the only individual measure of offensive linemen that we have. You can’t get much from “he’s been one of Team A’s five preferred linemen 16 times since he started school here.”

It’s the same with returning starters. We use it because it exists. It is fine as a really quick snapshot, but we know that one team’s six returning offensive starters aren’t another’s. What about go-to guys? Returning backups? And quarterbacks are worth more than other starters, right?

In 2016, I began using a returning production figure based on what seems to have the most impact on year-to-year performance. With what is now a few years’ worth of data, let’s take a look at some updated correlations.

Returning experience on the line doesn’t have nearly the statistical impact that we think it will. But with more data in the bank, we can see there’s a little correlation.

The higher the number, the more likely returning production in these areas is to coincide with strong offense:

The conclusion remains: Continuity in the passing game matters a hell of a lot, and continuity in the run game doesn’t have as strong an impact.

On defense, where returning production appears to matter more in general, the correlations are both stronger and more diverse. Since teams use different numbers of defensive linemen, linebackers, and defensive backs, I look at both unit-specific categories and those for defense as a whole.

The main takeaways are similar to last year: Disruption and continuity in the secondary are key. And the ability to get hands on passes is harder to replicate than any other.

So what does this mean for 2018? As with last year, I used categories like the ones above, weighted for largest effect — so returning quarterbacks, receivers, and defensive backs carry more heft — to create numbers for offense and defense.

Over the last four years, 37 teams have returned at least 80 percent of their production based on current calculations; 32 of them (86 percent) improved, and 22 (59 percent) improved their adjusted scoring margin per game by at least six points.

Meanwhile, 56 teams returned under 50 percent of their production; 48 of them (86 percent) regressed, 27 (48 percent) by at least a touchdown.

Thus far for 2018, 11 teams return 80 percent or more, and 11 return under 50 percent.

Here are 2017’s top 10 teams, according to S&P+, ranked in order of 2018 returning production:

2017 was supposed to be a retooling year for 2016 national champion Clemson. The Tigers were limited in the passing game, and it caught up with them, but not until the semifinals against Alabama. That they managed to get that far was impressive, and now they’re returning basically as much as any of last year’s other top 10 teams.

The announced return of virtually the entire defensive line was a surprise, but the Tigers’ depth is impressive — by my count, they are scheduled to bring back 100 percent of their passing yards (plus two five-star underclassman quarterbacks), 100 percent of their running back rushing yards, 56 percent of receiving yards, 100 percent of defensive line tackles, 76 percent of linebacker tackles, and 73 percent of defensive back tackles.

There are questions to answer in the receiving corps (Deon Cain and Ray-Ray McCloud are gone) and on an offensive line that loses three all-conference starters. But recruiting should assure the replacements are high-caliber athletes. Clemson is in great position to improve in 2018.

Somehow, Washington quarterback Jake Browning and running back Myles Gaskin still have eligibility remaining, and they’ll head an offense that returns six linemen with starting experience and 57 percent of last year’s receiving yards. The defense loses star tackle Vita Vea ... and very little else.

UCF must replace linebackers Chequan Burkett and Shaquem Griffin, receiver Tre’Quan Smith, and head coach Scott Frost. But the latter doesn’t apply to this formula, and quarterback McKenzie Milton will have a lot of familiar faces.

Both of the Big Ten’s Michigan schools are in the top 15. Mark Dantonio’s Spartans lead after surging back into the S&P+ top 25 in 2017, a year ahead of schedule. It’s obviously difficult to talk too much about State’s future at the moment, however.

Down the road, Jim Harbaugh’s Wolverines return quite a bit, too, especially on defense. Michigan’s 2017 season felt disappointing, but it wasn’t far off what was projected; 2017 was always about building for 2018.

Well, now it’s 2018. Put-up-or-shut-up time.

Former Penn State offensive coordinator Joe Moorhead took over for Dan Mullen, and he inherits a far greater level of expectation than Mullen did when he arrived in 2009. Not only has MSU achieved at an unprecedented level (eight straight bowls, plus at least nine wins in three of the last four years), but the Bulldogs also return so much:

In terms of combined experience and talent, this could be one of MSU’s most impressive teams. Moorhead won’t get much of a breaking-in period in Starkville, will he?

Average returning production by conference:

The Pac-12 graded out as the worst of the power conferences in 2017. Thanks to USC and Washington suffering early upset losses, the conference was basically eliminated from national title contention midway through the season, and it finished with only one team in the S&P+ top 25.

And now it returns the least production of any of the P5s. Yikes.

Granted, this year’s averages are pretty damn tight. Among FBS’ 10 conferences, nine return between 63.7 and 66.5 percent of their production; only the AAC falls outside of that range (also note every other Group of 5 league ranking Nos. 1 through 4).

Still, when you slump like the Pac-12 did, you hope it’s because of youth and that there’s growth on the horizon. That’s not automatically the case here.

Average returning production by power conference division:

The Pac-12, SEC, and Big Ten all have some imbalance issues at the moment, each sporting one division (the Pac-12 North, SEC West, and Big Ten East) that is quite a bit stronger than the other. In all three instances, the stronger division is scheduled to return quite a bit more than the weaker division.

This is particularly pronounced in the Pac-12, where five of six North teams rank among the top half of the country in returning production and five of six South teams rank 79th or worse.

At least the ACC’s balancing out a little bit.