Saturday, December 3, 2016

Guess the Lines Week 14

Here are the week 13 results and week 14 predictions for this installment of "Guess the Lines". This is a weekly feature in which I put my Vegas NFL rankings to the test by predicting the point spread of upcoming NFL games. I compare the accuracy of my prediction against those of Bill Simmons and Cousin Sal, as featured on their weekly NFL podcast. In addition, I also calculate an implied point spread from ESPN Chalk's weekly Vegas NFL rankings.

Here are the week 13 results. Bill Simmons wins this week, with an impressive mean absolute error of 0.87 points. ESPN Chalk rankings continue to bring up the rear.

Turnover Index Week 13

Here are the Turnover Index picks and results for week 13. The Turnover Index is a simple betting strategy based on the theory that the market overvalues defensive turnovers when judging team strength. See here and here for more background.

Once again, we went 1-1 with our Week 12 bets, and our bankroll dropped by $6 from $1,052 to $1,046. We are now 6-4 against the spread on the season, with an ROI of 4.6%. Bets are sized according to the Kelly criterion.

Here are the 2016 season to date results:

weekbetswonstarting
bankroll
amount betprofitsending
bankroll
6 1 0 $1,000 $36 (3.6%) ($36) $963
7 1 1 $963 $10 (1.1%) $9 $973
8 1 1 $973 $38 (4.0%) $35 $1,008
9 3 2 $1,008 $64 (6.4%) $51 $1,060
10 2 1 $1,060 $15 (1.5%) ($7) $1,052
12 2 1 $1,052 $13 (1.3%) ($6) $1,046

Wednesday, November 23, 2016

Guess the Lines - Week 13

Here are the week 12 results and week 13 predictions for this installment of "Guess the Lines". This is a weekly feature in which I put my Vegas NFL rankings to the test by predicting the point spread of upcoming NFL games. I compare the accuracy of my prediction against those of Bill Simmons and Cousin Sal, as featured on their weekly NFL podcast. In addition, I also calculate an implied point spread from ESPN Chalk's weekly Vegas NFL rankings.

Here are the week 12 results. Cousin Sal was the winner for the second straight week, with a mean absolute prediction error of 1.22 points. My rankings and Bill Simmons' guesses were close behind. The ESPN Chalk rankings came in a relatively distant 4th.

Turnover Index - Week 12

Here are the Turnover Index picks and results for week 12. The Turnover Index is a simple betting strategy based on the theory that the market overvalues defensive turnovers when judging team strength. See here and here for more background.

There were no bets that satisfied our criteria for Week 11. We went 1-1 with our Week 10 bets, and our bankroll dropped by $7 from $1,060 to $1,052. We are now 5-3 against the spread on the season, with an ROI of 5.2%. Bets are sized according to the Kelly criterion.

Here are the 2016 season to date results:

weekbetswonstarting
bankroll
amount betprofitsending
bankroll
6 1 0 $1,000 $36 (3.6%) ($36) $963
7 1 1 $963 $10 (1.1%) $9 $973
8 1 1 $973 $38 (4.0%) $35 $1,008
9 3 2 $1,008 $64 (6.4%) $51 $1,060
10 2 1 $1,060 $15 (1.5%) ($7) $1,052

Wednesday, November 16, 2016

Guess the Lines - Week 12

Here are the week 11 results and week 12 predictions for the "Guess the Lines" prediction contest. This is a weekly feature in which I put my Vegas NFL rankings to the test by predicting the point spread of upcoming NFL games. I compare the accuracy of my prediction against the predictions of Bill Simmons and Cousin Sal, as featured on their weekly NFL podcast. In addition, I also calculate an implied point spread from ESPN Chalk's weekly Vegas NFL rankings.

Here are the week 11 results. Cousin Sal was the winner this week, narrowly edging out my rankings with a mean absolute prediction error of 1.07 points (compared to my 1.11). The ESPN Chalk rankings came in last, with an error of 1.46.

Saturday, November 12, 2016

Turnover Index Week 10

Here are the Turnover Index picks and results for week 10. The Turnover Index is a simple betting strategy based on the theory that the market overvalues defensive turnovers when judging team strength. See here and here for more background.

We went 2-1 with last week's bets, bringing us to 4-2 on the season, and an ROI of 6.0%. Bets are sized according to the Kelly criterion. Fortunately, our one loss was on a game that was just barely above the breakeven point, so it only cost us 0.4% of our bankroll. The model was more confident on our two winning picks, allowing us for a nice return on our 6.1% investment.

Here are the 2016 season to date results:

weekbetswonstarting
bankroll
amount betprofitsending
bankroll
6 1 0 $1,000 $36 (3.6%) ($36) $963
7 1 1 $963 $10 (1.1%) $9 $973
8 1 1 $973 $38 (4.0%) $35 $1,008
9 3 2$1,008 $64 (6.4%) $51 $1,060

Guess the Lines - Week 11 (plus Week 10 results)

The results are in. Who was right, the pundits or the models?

Last week, I launched a weekly feature that pits my Vegas NFL rankings against the instincts of Bill Simmons and Cousin Sal, as featured in The Ringer's "Guess the Lines" podcast. The podcast aired Monday, and I had results ready to go Tuesday, but other events interceded that night.

As a reminder, I am using my Vegas rankings for the NFL to predict the point spreads for future games. The rankings use point spreads from this season's games to reverse engineer an implied power ranking.

Opening lines tend to come out a week and a half in advance, and my rankings automatically update when they do. In order to make the test properly out of sample, I need to make my predictions almost a week in advance of The Ringer's Monday podcast. The predictions below are based on my rankings as November 1. The aGPF and hGPF columns are the away and home "Generic Points Favored" numbers from my rankings. The predicted point spread is just the difference between the two numbers plus a 2.5 point adjustment for home field advantage.