Nebraska wide receiver looks to make a catch against defender in end zone
Photo Credit: John S. Peterson

Inferring a 2021 Win Total from the Huskers’ Initial SP+ Rating

February 11, 2021

Well, here we go again. Nebraska football is ranked higher in the first SP+ rankings for the season ahead than almost anyone would think it should be. Let’s talk about that.

SP+ is one of ESPN’s primary predictive power rankings alongside the Football Power Index. According to the system’s creator, Bill Connelly, SP+ is “intended to be predictive and forward-facing.” All preseason rankings are that by default, but the difference with SP+ is that it is always that way. Teams aren’t necessarily rewarded or penalized for wins and losses during the season––which tends to drive people mad––they’re rewarded or penalized for playing well or playing poorly in a way that allows you to model future expectations.

It is, of course, a little different in the offseason. There are no games to go on, so the rankings at this point are made up of three factors: returning production, recent recruiting and recent performance. These are all things human pollsters consider to varying degrees in coming up with their preseason rankings, here it’s just a specific statistical model that is consistently being tweaked and improved based on how well it performs.

While on-field progress has been hard to see for Nebraska so far under Scott Frost, SP+ says it is happening. The 2018 Huskers were 60th to start the 2018 season, 45th to start 2019 (when Nebraska was showing up in preseason top 25s, failed to meet those expectations and pushed many Husker fans to swearing off hype forever), 25th to start 2020 and now 30th to start 2021 with a rating of 14.0, meaning SP+ views the Huskers as 14 points better than the average college football team.

Surprised? I was somewhat and that was knowing that Nebraska finished the 2020 season 31st in the final rankings, higher than just about anyone would put a team that went 3-5. Last year’s rating carries quite a bit of weight at this early stage, but I still thought losing leading wide receiver Wan’Dale Robinson and top running back Dedrick Mills, big hits to the returning production part of the equation, would drop the Huskers into the 40s.

Instead, Nebraska has its highest SP+ rating, not ranking, of the Frost era. Here’s what that progression looks like week by week since the first rating of 2018:

Why so high now? That’s a tough question to answer without knowing exactly what goes into SP+ and how it is weighted, but here’s a guess: Nebraska’s offense has been strong all three years when it comes to success rate, the ‘S’ in SP+. That’s the stat that means the most to winning, is the hardest to maintain and isn’t very random. A team is either good at staying on schedule or it is not; you don’t really luck your way into success here. The ‘P’ in SP+ is an explosiveness measure. That has been surprisingly lacking, for the most part, during Frost’s Nebraska tenure, but it’s also a volatile stat, similar to 3-point shooting. Great teams are both efficient and explosive. Nebraska has only consistently been the former, but, like a basketball team getting hot from beyond the arc, the latter should come around one of these days even if it’s temporary.

Despite having a middle-of-the-pack ranking in returning production on offense, Nebraska has done the hardest part well most of the time. That’s my read on why the Huskers consistently impress the SP+ model more than they do Husker fans. Defensively, Nebraska has returning production that would make a slight improvement in 2021 more likely than not. Combine the two, add a dash of special teams (still not great), and you have a top-30 team by this system.

That puts Nebraska one spot ahead of Minnesota and two spots ahead of Maryland, a team that had surprising success in 2020 (that I’m not totally buying as it pertains to seasons to come). The issue for the Huskers is that they will face five teams with a better rating in SP+ right now. We already knew this, but 2021 is yet another tough road for Nebraska.

But the Huskers’ inferred win total, using SP+, surprised me as well. This rating system is set up to do that. You take one team’s rating minus the opponent’s rating, add 2.5 points for home field advantage, and you’re left with a projected spread. For example, No. 30 Nebraska has a 14.0 rating and its Week 2 opponent, No. 77 Buffalo, has a -2.0 rating. Do the math––14 minus -2, plus 2.5 for Nebraska playing at home—and you’re left with a projected spread of Huskers -18.5.

With a projected spread you can pull up implied win probabilities and, because win probabilities can be added, you can arrive at an inferred win total for the season. Here’s how that looks based on the Huskers’ 2021 schedule (Note: There are no SP+ ratings for FCS teams, but I am certain that Nebraska’s win probability against Southeastern Louisiana will be 99% so that’s what I applied here):

DATEOPPONENTNU LINEWIN PROBABILITY
8.28Illinois-16.589.1%
9.11Buffalo-18.596.2%
9.18at Oklahoma+16.511.0%
9.25at Michigan State-7.070.3%
10.2Northwestern-17.593.7%
10.9Michigan-1.051.2%
10.16at Minnesota+2.046.6%
10.30Purdue-7.573.0%
11.6Ohio State+8.525.4%
11.13Southeastern LouisianaN/A99.9%
11.20at Wisconsin+11.020.1%
11.26Iowa+3.042.6%

Would you take seven wins in 2021? I think most Husker fans would. I’m a little skeptical of that number. I would’ve figured something between six and seven, but then again Nebraska was also higher in these rankings than I would’ve assumed. Practically speaking, I’ll be very surprised if a few of the actual spreads aren’t more than two or three points different from what you see above.

Nebraska could play as well as anyone could hope against Illinois—really good craic, as they say, if that game is played in Ireland—and I have a hard time seeing NU going off as an 18.5-point favorite over a good Buffalo program under the direction of one-time Husker assistant Lance Leipold. The Huskers will very likely be more than a 16.5-point underdog at Oklahoma, which is ranked third in these SP+ ratings.

Beyond that, the actual 2021 results will start to outweigh the preseason formula, but it’s still hard to see Nebraska (or anyone in the Big Ten outside of Ohio State, maybe) being a 17.5-point favorite over Northwestern. The Wildcats lose a lot and will likely take a step back, but that line could come down by at least three points and I’d still take Northwestern to cover based on the history of that series. It’s really hard to blow out the Wildcats. Meanwhile, Ohio State makes blowing teams out look easy, particularly Nebraska minus the 2018 blip. The Buckeyes will be a double-digit favorite come November barring something totally bizarre on either side.

The rest of the schedule? I could see those projected lines being within a point or two of the actual lines. Does it add up to seven wins in 2021?

I’m not ready to go there yet, but that’s what we can infer from a strong rating system that just happens to see more to like in Nebraska than most.

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