Posts Tagged ‘ESPN SPI’

Paging Will Hunting: ESPN’s Soccer Power Index

Soccer. Front Page, Great, right?


ESPN unveiled its shiny new Soccer Power Index (“SPI”) this morning and all I can say is…my head hurts. I think I am a fairly intelligent dude–college degree, former investment banker,  fairly well read–but I couldn’t figure out how the below formula helps me predict who is going to win the World Cup.

AGS = ((GS-OPP_DEF)/( MAX(0.25,OPP_DEF*0.424+0.548))*(AVG_BASE*0.424+0.548)+AVG_BASE

(Yes, this is an actual formula from the SPI “methodology” article.)

In what can only be called the continuing Americanization of the beautiful game, directed its stat geeks to concoct a complex formula that would serve as a predictor of international competition, player impact and the surface temperature on Mars at precisely 8:05am on June 12th.

First and foremost, I applaud for spending the resources on this endeavor, attempting to objectify the sport and elevating it to home page content.

But what’s the point of going to such lengths to come up with a less subjective who’s-better than who list? According to the SPI “purpose” article, “[the] SPI is designed to serve as a general guideline…it will start a few debates — but [isn’t] expect[ed] it to settle them.”

Couldn’t that just have been done by compiling a “power poll” by a panel of “experts” or even readers of TSG? (The latter of which would certainly be more accurate.)

Considering it took two lengthy articles (which I did read) to explain the approach and methodology complete with competitiveness coefficients, recentness factors and composite ratings, I am not inclined to argue the methodology of the formula. One read-through, however, does raise a lot of questions.

In general, the complexity of the methodology in which so much is thrown into a black box that spits out a rating does lead to a lot of subjectivity around what is and what is not counted (and how) which inherently makes this less objective. Not to mention the fact that the SPI is a product of  a former baseball stat geek; though Nate Silver is a well-respected statistician in his own right.

spi rankGetting out of the weeds a bit, perhaps the better question is this: Can the quintessential team game filled with nuance be explained solely through statistics?

The answer is some shade of “no,” but in an American sports landscape filled with PER numbers (basketball), VORP stats (baseball) and QB Ratings (football) thinks that’s what soccer needs in order to sell it to the American public in advance of the World Cup.

The SPI as an arbiter of team strength will no doubt attract some American stat geeks to take a closer look at the sport, but 8,000 words of explanation about a single number doesn’t make the game more accessible to the curious sports fan wishing to kick the tires of a “new” sport.

At the end of the day, soccer fans have another list to debate in addition to the FIFA rankings. And the Will Huntings of the soccer world have some new luscious numerical details to delve into.

To the right is the top 20 of’s SPI (full list at the link). Brazil and Spain come out #1 and #2, respectively. England, after missing out on Euro 2008, but sailing through WC qualifying ranks 3rd and the US sits in 14th (4 spots ahead of Mexico).

Of note on the United States is that the SPI predicts the USMNT will score 2.30 goals “against average teams” yet in reality, the US has only eclipsed the two-goal mark 5 times in their last 24 contests.

Let the arguing begin.


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