## Sunday, November 20, 2011

### How Did Vegas Do Predicting MLB Games?

A good way to tell how well Vegas (and my simulator) did at predicting winners during the season is to compare blocks of games that had similar odds to each other. For example, I took the 100 games that had the highest favorite to win and calculated the average Vegas win expectancy of those games and compared across the board to my simulator and the actual results. I did this for all 100 blocks of games as well as blocks of 300 and blocks of 600. The smaller the block size the more noise you will have but the more interesting trends you will see. Below are tables of those three types of blocks of games.

100 Blocks of Games 300 Blocks of Games 600 Blocks of Games
BlocksVegSimActual  VegasSimActual  VegasSimActual
1-1000.69100.67230.6700 1-3000.66150.64760.6267 1-6000.63960.63010.6450
101-2000.65490.64080.6100 301-6000.61770.61260.6633 601-12000.58310.57620.5867
201-3000.63870.62970.6000 601-9000.59260.58580.5700 1201-18000.54860.54100.5517
301-4000.62720.62170.6500 901-12000.57360.56660.6033 1801-24140.51710.51380.5220
401-5000.61770.60590.6400 1201-15000.55690.55040.6033
501-6000.60810.61010.7000 1501-18000.54040.53170.5000
601-7000.59930.59430.6900 1801-21000.52510.51960.5033
701-8000.59270.58210.5100 2101-24140.50950.50830.5399
801-9000.58580.58100.5100
901-10000.57880.57840.5900
1000-11000.57340.55950.6100
1100-12000.56850.56200.6100
1201-13000.56290.55280.6500
1301-14000.55700.55190.6000
1401-15000.55070.54660.5600
1501-16000.54610.53600.5500
1601-17000.54020.52930.5400
1701-18000.53480.52980.4100
1801-19000.53030.53220.4600
1901-20000.52520.52300.5300
2001-21000.51990.50340.5200
2101-22000.51420.51110.5000
2201-23000.50980.51100.5400
2301-24140.50500.50350.5702