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Stat Pundit Rankings: MLB win over-unders

Sep 30

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About two weeks ago, I used some familiar metrics to analyze how analytics-based websites performed as far as predicting MLB win totals. With the regular season now complete, winning bets have been cashed, and the official performance for each site is listed below:

O/U: The Hilton’s over/under for each team

BP: Baseball prospectus

TR: Team Rankings (caveat on the linked page: the site stresses their MLB predictions are a work in progress)

DP: Davenport

Zips: ZIPS projection system (espn.com)

PM: Prediction Machine

TB: Trading bases, an avid blogger and book-writer

Here are my metrics

MSE: Averaged squared error between the prediction and the win totals (lower is better)

MAE: Averaged absolute error between the prediction and the win totals (lower is better)

Corr: Correlation between the predicted and the win totals (higher is better)

Results

O/U BP TR DP Zips PM TB
MSE 82.65 74.40 98.60 85.43 87.53 94.27 71.53
MAE 7.37 7.33 8.40 7.37 7.40 7.86 6.93
Corr 0.66 0.70 0.58 0.64 0.64 0.59 0.71

Baseball Prospectus and Trading Bases appear to offer the only clear advantage over the Las Vegas line, at least among these predictions, as judged by a higher correlation and a lower MSE between observed and predicted values. On average, TB was the only prediction site to finish, on average, within seven wins of the actual results.

A savvy bettor would’ve finished 12-9 on bets where BP differed by the Las Vegas O/U by more than two wins, and 10-6 using the same cutoff for TB. Picks that BP and TB agreed (by more than 2 predicted wins) on finished 7-4

Here are the Vegas lines and each site’s picks. In some cases, the projected total wins might not add up to 82 per team, most likely due to rounding errors.

Team O/U BP TR DP Zips PM TB Actual
Diamondbacks 82.5 85 83 81 85 76.8 80 81
Braves 86.5 83 85 85 91 86.6 82 96
Orioles 78.5 75 81 75 82 79.2 76 85
Red Sox 82.5 85 79 85 84 80.5 83 97
Cubs 72.5 77 73 76 74 75.8 69 66
White Sox 80.5 76 83 76 80 85 78 63
Reds 90.5 92 84 86 90 91.1 84 90
Indians 78.5 80 74 79 80 76.8 85 92
Rockies 71.5 71 75 74 70 77.5 70 74
Tigers 92.5 91 86 95 91 89.7 95 93
Marlins 63.5 67 75 65 65 65.3 64 62
Astros 58.5 63 67 72 57 62.5 66 51
Royals 78.5 76 78 80 79 75 77 86
Angels 91.5 91 86 91 93 93.3 88 78
Dodgers 91.5 91 83 88 90 90.6 91 92
Brewers 81.5 78 83 78 81 77.6 78 74
Twins 68.5 65 74 69 66 70.9 66 66
Mets 75.5 80 78 76 66 76.8 74 74
Yankees 86.5 91 90 86 83 84.7 87 85
Athletics 84.5 83 86 84 78 85.3 85 96
Phillies 85.5 81 84 81 82 81 86 73
Pirates 77.5 80 77 81 77 74.8 79 94
Padres 73.5 76 78 76 73 72.7 81 76
Giants 87.5 85 85 92 87 85.1 88 76
Cardinals 82.5 85 86 83 85 85.1 90 97
Rays 86.5 87 88 86 88 89.5 93 91
Rangers 86.5 89 88 85 91 86.8 85 91
Blue Jays 88.5 84 78 86 94 87.5 82 74
Nationals 91.5 87 86 85 94 92.5 90 86
Mariners 77.5 78 79 73 74 74 78 71

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MLB over-unders: Can anyone beat Las Vegas?

Sep 19

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Back in March, several dozen websites, written by either professionals, bloggers, or, in some cases, professional bloggers, came out with predicted MLB win totals.

A predicted win total represents the number of wins this website or individual predicted for each major league team. These numbers can be easily compared to the Las Vegas line for each team (I used the one set by the Hilton) to determine if these predictions are worth our time, and, in some cases, our money.

Here are the sites I used:

O/U: The Hilton’s over/under for each team

BP: Baseball prospectus

TR: Team Rankings (caveat on the linked page: the site stresses their MLB predictions are a work in progress)

DP: Davenport

Zips: ZIPS projection system (espn.com)

PM: Prediction Machine

TB: Trading Bases, an avid blogger and book-writer

Here are my metrics

MSE: Averaged squared error between the prediction and the win totals*

MAE: Averaged absolute error between the prediction and the win totals*

Corr: Correlation between the predicted and the win totals*

*For win totals, I’m use each team’s estimated win totals from here (I’m too excited to wait until the end of the season!)

Results

O/U BP TR DP Zips PM TB
MSE 68.59 62.50 84.56 70.47 75.37 79.76 61.04
MAE 6.65 6.75 7.73 6.75 7.01 7.22 6.53
Corr 0.68 0.71 0.59 0.67 0.66 0.61 0.72

Baseball prospectus appears to offer the only clear advantage over the Las Vegas line, at least among these predictions, as judged by a higher correlation and a lower MSE between observed and predicted values. As for team rankings & prediction machine, their results were both disappointingly bad. (Note: Trading Bases came into the picture after the initial post, and also appears to be a clear winner). 

TeamRankings does offer this disclaimer about their projections:

A word of caution — while our preseason projections for other sports have proven to be useful indicators of where values may lie among the various full season futures bets, we’re not nearly as confident in our MLB preseason ratings. We’re publishing these in the interest of full disclosure, so that you know what the initial rating in our projection system was for each team. We’re most definitely not recommending that you use these ratings and forecasts to go place preseason bets.

Here’s the table of predicted wins for each site.

Team O/U BP TR DP Zips PM TB Simulated Wins
Diamondbacks 82.5 85 83 81 85 76.8 80 82.5
Braves 86.5 83 85 85 91 86.6 82 95.8
Orioles 78.5 75 81 75 82 79.2 76 86.2
Red Sox 82.5 85 79 85 84 80.5 83 97.2
Cubs 72.5 77 73 76 74 75.8 69 67.5
White Sox 80.5 76 83 76 80 85 78 64.2
Reds 90.5 92 84 86 90 91.1 84 92
Indians 78.5 80 74 79 80 76.8 85 87.9
Rockies 71.5 71 75 74 70 77.5 70 72.9
Tigers 92.5 91 86 95 91 89.7 95 94.5
Marlins 63.5 67 75 65 65 65.3 64 60.1
Astros 58.5 63 67 72 57 62.5 66 54.9
Royals 78.5 76 78 80 79 75 77 85.1
Angels 91.5 91 86 91 93 93.3 88 79
Dodgers 91.5 91 83 88 90 90.6 91 92.5
Brewers 81.5 78 83 78 81 77.6 78 73.3
Twins 68.5 65 74 69 66 70.9 66 69.6
Mets 75.5 80 78 76 66 76.8 74 73
Yankees 86.5 91 90 86 83 84.7 87 84.9
Athletics 84.5 83 86 84 78 85.3 85 94.6
Phillies 85.5 81 84 81 82 81 86 75.7
Pirates 77.5 80 77 81 77 74.8 79 92.1
Padres 73.5 76 78 76 73 72.7 81 76.1
Giants 87.5 85 85 92 87 85.1 88 75.2
Cardinals 82.5 85 86 83 85 85.1 90 94.6
Rays 86.5 87 88 86 88 89.5 93 89.2
Rangers 86.5 89 88 85 91 86.8 85 88.1
Blue Jays 88.5 84 78 86 94 87.5 82 73.8
Nationals 91.5 87 86 85 94 92.5 90 86.3
Mariners 77.5 78 79 73 74 74 78 71.4

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