Hot Reads: It Was a Good Year for ESPN's FPI
Photo Credit: Aaron Babcock

Hot Reads: It Was a Good Year for ESPN’s FPI

January 22, 2018

There was a stretch last spring when FPI became a dirty word in Nebraska. That’s ESPN’s Football Power Index, of course, and its earliest projection for Nebraska’s 2017 record was 5.5-6.5. While I felt like I had a good sense why the Huskers win total was so low, I was definitely part of the chorus that thought Nebraska would be better than that. If you were giving me an over-under at 5.5, I was firmly over.

ESPN’s Nebraska win total was one of the five biggest departures from the Vegas totals, which Seth Walder noted in July:

Don't be fooled by the Cornhuskers' 2016. It was nothing special.

Nebraska had the single-worst FPI among Power 5 schools with at least nine wins last season, which gives you a pretty good sense of how unimpressive the season actually was. The Cornhuskers finished the season with an FPI of 7.0, 48th in FBS, getting edged out by fellow nine-win Big Ten school Minnesota (which FPI also rates lower relative to Vegas this season).

So the reality is that Mike Riley enters this season with two disappointing campaigns under his belt. And FPI doesn't see a reason for it to turn around this season, either.

FPI was right, of course. So right that with the resulting new AD, coaching staff and hope in place, it feels like a lifetime ago. But as someone who pays close attention to this sort of thing, I never really stopped thinking about the conversation around Nebraska’s number. It was a common enough topic that I was brought on Husker Sports Nightly to talk about it. Everybody was interested in – or maybe just disgusted with – FPI. (Should note here that FPI differs somewhat from a plain power ranking system in that is designed to be predictive. That’s the stated goal.)

So how did the system do as a whole in 2017? Pretty well. Well enough that ESPN’s Walder, part of the analytics department, took a bit of a victory lap last week:


And while FPI doesn't want to brag, when we look at those prediction metrics, we see that it had a fantastic year in 2017. FPI's average absolute error was 12.4, so the average margin of victory was 12.4 points different than our predicted margin of error. That might sound like a lot (a lower error is better), but when predicting 780 football games, that's actually very good. And it's all relative to other models. In both error categories, FPI had a lower (better) score than any other public model out there. Here, see for yourself! 

In addition, in average squared error FPI also beat the Vegas opening line. Over the long haul, the Vegas lines are essentially a theoretical limit for a public model. If a public model were consistently beating Vegas, it would be used by bettors or sports books and the line would shift toward the model.

I noted this when writing about the Nebraska projection last April, but FPI had a pretty solid track record coming into the 2017 season. The previous year it ranked fourth in absolute mean error (removing the Vegas lines, prediction averages and other things includes), and in 2015 it ranked ninth.

With the benefit of hindsight, FPI’s 5.5 wins for Nebraska should’ve given me more pause than it did and I felt like I was closer to FPI’s “side” in that discussion than most. Of course there are outliers, and it’s understandable that fans would slot their team in the “we’ll defy the odds” category.

Nebraska wasn’t in that category. Florida State was. Preseason FPI had the Seminoles No. 3 with 10.2 projected wins. It had UCF at No. 63 and 7.6 projected wins.

Remember the latter, I guess, when the 2018 projections roll out and Nebraska is – and I’m totally guessing here – somewhere around the six-win range again. Maybe this is the year Nebraska actually lands in the “defy the odds” category. Some teams have to.

The Grab Bag

  • Zach Martin, a quarterback at Northwest Missouri State and Iowa Western, tweeted that he is joining Nebraska's staff as a GA.
  • Nebraska's quarterback battle makes ESPN's list of 20 to watch this spring.
  • Good read on an intriguing hire by Oklahoma State: Bob Stitt is on board as an offensive analyst for the Cowboys.
  • ICYMI: Nebraska added the 19th commit to its class last night. Greg Smith offered five thoughts on Braxton Clark here. Also, we'll get you read for Nebrasketball's game against Ohio State tonight with a preview from Derek Peterson and a column from Jacob Padilla.

Today's Song of Today

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