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Stanford vs. San Diego State: Odds, betting lines, and computer predictions

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The Cardinal are favored, but opinion about the Aztecs is all over the place.

NCAA Football: Utah State at San Diego State Jake Roth-USA TODAY Sports

LAS VEGAS LINES AND ODDS

The sports books opened Stanford vs. San Diego State with the Cardinal favored by 9 points and the spread has stayed steady right at Stanford by 9. The lack of change in the line reflects that early bettors have laid equal amounts of their money down on both Stanford and San Diego State to cover the spread.

Vegas lines and odds aren't meant to be predictive. They are made to entice betting in equal portions on each side of the spread. However, combining the line and the over/under usually ends up close to some computer models. After all, Vegas is very good at this and it is a lot of fun.

Combining the line and the over/under, the Vegas combo has Stanford winning 29-20.

2017 Stanford Vegas record against the spread: 1-1

2017 Vegas record predicting Stanford football outcomes: 2-0

PREDICTIVE RANKINGS

Some computer rankings are designed to provide a built-in predictive element by comparing the ratings of two teams.

Some of the best ratings out there come from Football Outsiders. The most famous is Jeff Sagarin's for USA Today, previously used in the BCS computer rankings. I've included a couple others from around the web as well.

FOOTBALL OUTSIDERS F/+

F/+ is a combination of Bill Connelly's S&P+ and Brian Fremeau's FEI ratings. The ratings are usually pretty solid in factoring all the many variables involved in ranking college football teams that have a relatively low level of common opponents.

F/+ does not predict a final score but does give an expected margin. F/+ likes Stanford by 10 points with a 72.3% Win Probability.

The F/+ ratings list Stanford # 9 (-1 from last week) and San Diego State # 47.

Football Outsiders site only lists the ratings in order, but Bill Connelly posts predictions on SB Nation.

Bill's S&P+ picks predict The Cardinal by 12.5 points (winning 34.7-22.1) and give Stanford a win probability of 76.6%. Connelly picks Stanford at -9 to cover the Vegas spread.

Bill Connelly’s 2017 record predicting Stanford against the Vegas spread: 1-1

Bill Connelly’s 2017 record predicting Stanford football outcomes: 2-0

SAGARIN

Stanford is ranked #16 (-2) with a rating of 84.59.

San Diego State is ranked #52 with a rating of 74.24.

Sagarin’s formula currently values home field advantage as worth 2.41 points. So subtracting the difference between the ratings and then adding 2.41 in favor of the home team, the Aztecs of San Diego State, Sagarin has Stanford favored by 8 points (7.94).

Sagarin’s 2017 record predicting Stanford football outcomes: 2-0

BILLINGSLEY

Billingsley's ranking was also previously used by the BCS. With the BCS restriction to remove margin of victory no longer a consideration, Billingsley has created a version of his formula that accounts for margin of victory.

Stanford is ranked #13 with a rating of 102.221.

San Diego State is ranked #39 with a rating of 97.444.

The difference is 5 (rounded up from 4.777) points. Billingsley does not provide a home-field advantage factor, but let's apply the standard 3 points to the Aztecs and say Billingsley has Stanford by 2 points.

Billingsley’s 2017 record predicting Stanford football outcomes: 2-0

DONCHESS INFERENCE RATING

Donchess boils down the ratings directly into digestible scores and probabilities, no math required.

Donchess predicts a Stanford win 27-22 and gives Stanford a win probability of 68.6%.

Donchess’ 2017 record predicting Stanford football outcomes: 2-0

ESPN FOOTBALL POWER INDEX

Last week, Rule of Tree readers were in a frenzy as this article omitted to include the ESPN Football Power Index (FPI). The reason, of course, was that ESPN’s FPI was one of the very few computer formulas that liked Stanford to beat USC. Stanford fans were clamoring to find a computer somewhere that preferred the Cardinal over the Trojans.

So, here we are, adding the FPI to this weekly article.

FPI has Stanford ranked at #9. This week’s opponent, San Diego State, is #59.

FPI doesn’t provide a prediction as far as a score but does give a win probability. FPI suggests that Stanford has an 84.9% win probability over San Diego State.

FPI’s 2017 record predicting Stanford football outcomes: 1-1

COMPOSITE RATING

There are a lot of computer ratings that aren’t packaged with a predictive ability. There are also a ton of computer ratings, period. Kenneth Massey, whose ratings were also part of the old BCS computer formula, hosts on his site a composite ranking of 106 computer ratings across the internet.

In that composite, Stanford ranks #13 and San Diego State ranks #33.

The overall ability of these models to predict the outcomes of the Stanford games this year is impressive. Combined they are 11-1. The only formula with a blemish is the ESPN FPI.

The FPI is also the most dramatic this week concerning this game. FPI ranked Stanford the highest of any of the formulas. FPI also had San Diego State ranked the lowest.

It is clear to me that the computer formulas are all over the map on SDSU. The range of results on the Aztecs is from 33rd to 59th. That’s a 26-spot difference! That’s enormous when you consider that there are only 130 teams. That’s a ranking volatility of 20%. (In contrast, Stanford sits somewhere between 9th to 13th.) Simply put, some have SDSU nearly twice as low on the rankings than others. So, what do we make of San Diego State?

The Aztecs looked impressive on the road last week when they defeated Arizona State 30-20. SDSU’s head coach Rocky Long is known for having an aggressive defensive play calling style. Long will send the blitz frequently from all parts of the field. This can really confuse opposing quarterbacks.

Keller Chryst will need to be the intellectual standing in the pocket behind the brutality if Stanford wants a comfortable game Saturday night.

Stanford will have a good challenge in San Diego this weekend despite the unanimous predictions behind the Cardinal to win. After all, the computer formulas aren’t really sure what the Aztecs are at this point. In this way, I see SDSU as a wildcard. If a wildcard is in the deck, you can never be too sure about what is going to happen.