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The Vegas Lines Matrix has Auburn’s cells getting greener and greener

For those of us constantly obsessing over how well Auburn would stack up against the rest of the SEC, Max Mirable created this handy table – the Vegas Lines Matrix. For more information on what the Vegas Lines Matrix is, how it works, and why you should care, check out a previous column.

... scaling percentage-chance-predictions in a single bound.

Changes this week

Based on how all teams played last week, I (acting on behalf of Vegas bookies) have adjusted the matchup lines you could expect were these teams to play this week.  A few things to mention first: in order to “improve” a team’s odds, one of three things needs to occur: 1) the team needs to have improved on their per game statistics in the past week, or 2) their opponent’s per game statistics need to have gotten worse, 3) the team needs to have moved up in the polls.

Led by Heisman front-runner Cam Newton, Auburn put up 65 points against the Razorbacks, who had the SEC’s #2 and the nation’s #13 scoring defense, and moved up two spots to #5 in the polls.  With the exception of a small move in the line against Auburn in the Georgia game, all lines moved in Auburn’s favor this week.
In Auburn’s remaining games, we see the following changes:

LSU at Auburn: Line moved from Auburn being a 5.5-point favorite to a 7-point favorite.
Auburn at Ole Miss:  Line moved from Auburn being a 7.5-point favorite to a 10-point favorite
Chattanooga @ Auburn: This game is off the board, Auburn would likely be a 45-point favorite.
Georgia @ Auburn: Line moves from Auburn being a 17 point favorite to a 16.5-point favorite.
Auburn @ Alabama: Line moves from Auburn being a 9.5-point underdog to a 7.5-point underdog.

(As always, click to enlarge.)

How the Vegas lines Matrix compares to the actual Vegas lines

My predictions are again relatively close to what Vegas is currently saying, the biggest difference being a 4.5-point difference in the South Carolina @ Vanderbilt game. Last week, my Vegas lines model again underestimated a resilient Kentucky team, or maybe it overestimated South Carolina. Out-of-conference games do not currently have any predictions in the Vegas Lines Matrix.

Probabilities Matrix
We can use these odds from the above color-coded Vegas lines matrix to impute the implied probability of winning in these matchups.  These probabilities are calculated using thousands of prior games.  For example, let’s consider the actual LSU @ Auburn spread, where Auburn is a 6-point home favorite.  In the past 10 years (the period my data covers), there have been 133 games where the home team was a favorite by exactly 6 points.  In these 133 games, the home team won 91, and lost 42, for an implied win probability of 68.4%.  If the line moves ‘down’ to -5 points, historically we observe: 71 games, 47 wins for a win percentage of 66.2%.  If the line moves a point in favor of the Tigers to -7, we see: 212 games, 142 wins for a win percentage of 67.0%.

By populating the above matchup matrix with these probabilities, we can ‘simulate’ the remainder of the season, and calculate such things as a team’s expected record or probability of going undefeated.  Note that the probabilities actually displayed here are a 3-line moving average, so a 6-point home favorite would use all of the games mentioned above (lines at -5.5, -6, -6.5) to calculate a weighted average to smooth out inconsistencies from occasionally sparse data at certain line values.

As with the above matrix above, the values are color coded relative to the home team’s chances of winning.  The greener the cell, the more likely the home team is to win.

For the second consecutive week, Alabama failed to cover the point spread and Vegas is slowly but surely re-evaluating how good a team they really are. The Tide has a 21.5% chance of winning out with three tricky games remaining: @ LSU, Mississippi State, and Auburn.  A one-loss Alabama team with wins over these three top 25 teams and a gimme win against whichever team manages to lose the fewest games from the SEC East would likely propel Alabama all the way into the BCS title game.  That said, the same story holds true for both Auburn and LSU.   If either set of Tigers were to run the table, they would do so over three top 25 teams.  The BCS computers already like the schedule strength of the SEC, and the voters are unlikely to rank either TCU or Boise above an undefeated SEC team.  Everyone knows that the SEC has never lost in the BCS title game; that’s the kind of stat that voters tend to remember when deciding how to rank their teams at the end of the season. Stay tuned for an article predicting how the BCS is likely to shake out.

Auburn has a 12.7% chance of winning out and going undefeated prior to the SEC title game, up from 6.4% last week.  However, Alabama has a 21.5% chance of going undefeated in its remaining schedule, and LSU has an 8.4% chance of running the table.

Predicted Final Standings

Things are beginning to sort themselves out a little bit now that we’re more than half-way through the season.  Auburn now looks to be the front runner in the SEC, displacing an LSU team that struggled mightily to move the ball against McNeese State.  Alabama retains the #3 position in the West, with Arkansas and a surging Mississippi State team battling it out for fourth place.   Ole Miss may have one of the nation’s hardest remaining schedules ahead of them and could very well miss a bowl game this year.  That’s what happens when you lose to Vanderbilt.

In the SEC East (which is now just 2-10 against the SEC West), South Carolina still looks like the team to beat, despite last week’s loss at Kentucky.  Florida looks in good shape to join Kentucky for some pre-Jan 1 bowl games.  Georgia will need to win this weekend at Kentucky to have a chance at a 6-win season.

Mac Mirabile is a 2002 graduate of Auburn’s economics and journalism departments. During his time at Auburn, he was a copy and photo editor with The Auburn Plainsman. He has a master’s in economics from UNC-Chapel Hill and has written numerous academic publications on college football, the NFL, and gambling markets. His previous columns can be found here. He can be reached at [email protected]

About Mac Mirabile

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