Just thought I'd make a comment on how my algorithm differs from Laxpower.com's. Basically, I am solving a least squares problem in linear algebra for those who know what that is. Essentially, I use a similar strategy to Laxpower, in that I am attempting to make
P(i) - P(j) = D(i,j)
where P(i) and P(j) are the power ratings for teams i and j, and D(i,j) is the goal differential for those two teams for when they played each other head to head. I have not implemented a home field advantage, but it would be reasonably easy to do.
I implement this by setting up and solving the equation
M*A*P=D
where P is the list of power rankings for all the teams (which is unknown), and D is the list of goal differentials for all the games. A is simply a matrix which maps the correct power ranking with the correct goal differential. M is a masking matrix which simply eliminates the entries of A that represent games that haven't happened or never will. Then I use a linear equation solver to find P in a least squares sense (I use MATLAB's \ operator).
Friday, February 19, 2010
MCLA D1 Power Rankings
I delved into the world of power rankings today. Here are my MCLA D1 power rankings early in the season. I'll update periodically. Compare to laxpower.com:
| 1 | 'Indiana' | 28.75 |
| 2 | 'Simon Fraser' | 28.07059 |
| 3 | 'Georgia' | 27.32143 |
| 4 | 'Georgia Tech' | 24.32143 |
| 5 | 'Florida State' | 24 |
| 6 | 'Minnesota - Duluth' | 24 |
| 7 | 'Vanderbilt' | 23.32143 |
| 8 | 'Mississippi' | 23.32143 |
| 9 | 'Oregon' | 22.97059 |
| 10 | 'SMU' | 21.75 |
| 11 | 'Lindenwood' | 21 |
| 12 | 'Colorado State' | 21 |
| 13 | 'Chico State' | 21 |
| 14 | 'Central Michigan' | 21 |
| 15 | 'Florida' | 21 |
| 16 | 'Cal Poly - SLO' | 20.41176 |
| 17 | 'Arizona State' | 20.35294 |
| 18 | 'California' | 19.77059 |
| 19 | 'Chapman' | 19.11765 |
| 20 | 'Baylor' | 18.75 |
| 21 | 'Brigham Young' | 18.52941 |
| 22 | 'Texas State' | 18.25 |
| 23 | 'Western Washington' | 18.07059 |
| 24 | 'Miami (FL)' | 18 |
| 25 | 'Central Florida' | 18 |
| 26 | 'Alabama' | 17.89286 |
| 27 | 'Texas' | 17.5 |
| 28 | 'UC Santa Barbara' | 17.47059 |
| 29 | 'Minnesota St. Mankato' | 17 |
| 30 | 'Arizona' | 16.25 |
| 31 | 'St. John''s (MN)' | 16 |
| 32 | 'Hendrix (D-III)' | 16 |
| 33 | 'Rice' | 14.5 |
| 34 | 'Reinhardt' | 14.32143 |
| 35 | 'Middle Tennessee' | 14.17857 |
| 36 | 'South Florida' | 14 |
| 37 | 'Palm Beach Atlantic' | 14 |
| 38 | 'Loyola Marymount' | 13.64706 |
| 39 | 'Stanford' | 13.17059 |
| 40 | 'Washington' | 13.07059 |
| 41 | 'North Florida' | 13 |
| 42 | 'Missouri' | 13 |
| 43 | 'North Carolina State' | 12 |
| 44 | 'Grove City' | 12 |
| 45 | 'USC' | 11.97059 |
| 46 | 'Oregon State' | 11.87059 |
| 47 | 'Texas Tech' | 11.75 |
| 48 | 'Washington - St. Louis' | 11 |
| 49 | 'UC San Diego' | 11 |
| 50 | 'Toledo' | 11 |
| 51 | 'Texas A&M' | 11 |
| 52 | 'Tennessee' | 11 |
| 53 | 'St. Cloud State' | 11 |
| 54 | 'South Carolina' | 11 |
| 55 | 'San Diego State' | 11 |
| 56 | 'Portland State' | 11 |
| 57 | 'Pittsburgh' | 11 |
| 58 | 'Oklahoma' | 11 |
| 59 | 'Northern Colorado' | 11 |
| 60 | 'Nevada' | 11 |
| 61 | 'Nebraska' | 11 |
| 62 | 'Louisiana State' | 11 |
| 63 | 'Iowa' | 11 |
| 64 | 'Gonzaga' | 11 |
| 65 | 'Georgia Southern' | 11 |
| 66 | 'Ferris State' | 11 |
| 67 | 'Auburn' | 11 |
| 68 | 'Memphis' | 10.60714 |
| 69 | 'UCLA' | 10.35294 |
| 70 | 'Claremont' | 10.23529 |
| 71 | 'TCU' | 10 |
| 72 | 'Eastern Michigan' | 10 |
| 73 | 'Creighton' | 10 |
| 74 | 'Central Washington' | 10 |
| 75 | 'Santa Clara' | 9.823529 |
| 76 | 'San Diego' | 9.176471 |
| 77 | 'Southern Maine (D-III)' | 9.117647 |
| 78 | 'UC Davis' | 9 |
| 79 | 'Grand Canyon' | 8.294118 |
| 80 | 'UC Santa Cruz' | 8 |
| 81 | 'Clemson' | 7.666667 |
| 82 | 'UNLV' | 7.294118 |
| 83 | 'Southern Oregon' | 7 |
| 84 | 'Southwestern (D-III)' | 6.25 |
| 85 | 'Northern Arizona' | 6.25 |
| 86 | 'Cal State Fullerton' | 5.352941 |
| 87 | 'Kentucky' | 4.333333 |
| 88 | 'Carleton' | 4 |
| 89 | 'Willamette' | 1 |
| 90 | 'Stephen F. Austin' | 1 |
| 91 | 'Pacific Lutheran' | 1 |
| 92 | 'Marymount Coll. (CA)' | 1 |
| 93 | 'John Carroll' | 1 |
| 94 | 'Cornell College' | 1 |
| 95 | 'C. of Charleston' | 1 |
| 96 | 'Biola' | 0.235294 |
| 97 | 'Centenary (LA)' | 0 |
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