Sunday, January 22, 2012

Betting Market Power Rankings – Conference Finals Edition

by Michael Beuoy

Editor's Note: Michael submitted this earlier this week and I was late in posting it. EA

Here are the final Betting Market Power Rankings of the season, updated with the results of the prior week and the lines for this week. As promised last week, I will also revisit my predictions for the lines and over/unders for the conference final games.

Refer to last week’s post for more detail on the weights used.
Here is a glossary of terms:

LSTWK - The betting market rank as of the prior week
GPF - Stands for Generic Points Favored. It’s what you would expect a team to be favored by against a league average opponent at a neutral site.
oGPF – Offensive Generic Points Favored. The component of a team’s total GPF attributable to its ability to score points.
dGPF – Defensive Generic Points Favored. The component of a team’s total GPF attributable to its ability to prevent the other team from scoring points
O RANK – The team’s oGPF ranking.
D RANK – The team’s dGPF ranking.
GWP - Stands for Generic Win Probability. I converted the GPF into a generic win probability using the following formula: GWP = 1/(1+exp(-GPF/7)).

And here is the ranking table (the Rank column is relative to all 32 teams, but I’m only showing the 12 playoff teams):

RankTeamLSTWKGPFoGPFdGPFGWPORankDRank
1 NO110.010.5-0.50.81121
2 NE39.08.50.50.79212
4 GB26.56.50.00.72318
5 NYG84.53.51.00.6669
6 SF54.50.04.50.66142
7 BAL74.51.03.50.66113
8 PIT64.0-0.54.50.64161
9 ATL113.51.02.50.62126
11 DET92.53.5-1.00.60523
15 TEX160.5-2.53.00.52235
18 CIN19-1.0-1.00.00.472016
24 DEN24-4.0-3.0-1.00.372522

  • New England is the clear favorite among the field of four.





  • The remaining three teams all have identical GPF, indicating a competitive matchup in the Superbowl should New England happen to lose this weekend.





  • Here is how the model predicted the point spreads and over/unders for the two Conference Finals. I’ll show two versions of the predictions. The first is just copied from last week’s post. The second includes one more piece of information, which is how each team performed against the market’s expectation. As noted in my original post on this topic, the market appears to trust the outcome of each game with 15% credibility.


    Last Week

    GamePred LineActLineDiffPred OUAct OUOU Diff
     BAL @ NE 6.57.00.549.050.51.5
     NYG @ SF 3.52.5-1.042.042.00.0

    This Week (factors in Divisional Round results)


    GamePred LineActLineDiffPred OUAct OUOU Diff
     BAL @ NE 7.57.0-0.549.050.51.5
     NYG @ SF 2.52.50.042.042.00.0

    Last week’s prediction was fairly close (not as close as Brian’s tweet, but this week’s nudged closer due to the model factoring in the Giants and Patriots beating the market’s expectation by about 25 points and 20 points, respectively. SF also beat expectations, but only by about 7 points, while the Ravens performed as expected by beating the Texans by a touchdown.



    Editor's note: The last two tables are a revision from the original post. The tables had been switched in the original version.


    5 comments:

    Steve said...

    Based on last week's games, shouldn't the line line increase for NE and decline for Giants? You're showing the opposite.

    Steve said...

    Here's another way to look at it

    Based on "Future" odds, Patriots should be favored by 8¾ points today

    Hypothetical: Super Bowl February 5th; no action if teams do not play each other

    New York Giants -2½
    Baltimore Ravens +2½

    New York Giants +3
    New England Patriots -3

    Pats considered 5½ points better


    San Francisco 49ers -1½
    Baltimore Ravens +1½

    San Francisco 49ers +4½
    New England Patriots -4½

    Pats considered 6 points better


    Pats considered an average of 5¾ points better. Given home advantage 3 points, that means they should be favored by 8¾ points today, but in this game they are only 7 point favorites.

    Actually a full 2 points because sportsbooks are giving beneficial odds at 7 points.

    Steve said...

    What the odds should be in NFC championship game
    New York Giants -2½
    Baltimore Ravens +2½

    San Francisco 49ers -1½
    Baltimore Ravens +1½

    Giants considered 1 point better

    New York Giants +3
    New England Patriots -3

    San Francisco 49ers +4½
    New England Patriots -4½

    Giants considered 1½ points better

    Giants considered an average of 1¾ points better. Given home advantage 3 points for San Francisco, that means San Francisco should be favored by 1¼ points today. They are presently a 2 point favorite today, closer to the “correct odds” than in the AFC game, but still ¾ of a point too much.

    I’m also thinking that because the Giants played in San Francisco recently this season, home advantage isn’t quite as important as it typically is. On the other hand, bad weather, Manning was sick ... this game may be about right.

    Michael Beuoy said...

    Steve - you're correct. I think the tables got switched.

    Michael Beuoy said...

    Steve - Interesting analysis. Where did you get those "future" odds?

    According to the early odds on Footballlocks, the Pats are a 3 point favorite and the over/under is 55.

    My prediction from a couple weeks ago for that matchup was the Pats as a 4.5 point favorite and an over/under of 54.5.

    Giants outperformed the spread this week while the Pats underperformed, but I wouldn't expect a full 1.5 point move on the basis of that. Maybe Vegas is figuring in some sort of home field advantage, given that the Pats won't be too welcome in Indy? :)

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