Saturday, November 28, 2015

NFL Playoff Implications Week 12

Here are the playoff implications for the NFL's week 12 games. The purpose of this feature is to highlight games that have a significant impact on the playoff picture (see this post for background).

The playoff implications below are derived from a 50,000 round simulation of the remainder of the NFL season. I use my daily NFL rankings to simulate future games. I can group the simulation runs by the outcome of each game and then see how a team's playoff chances vary between the two groups. The interactive table at the bottom of the post will allow you to see corresponding results for any game or team. The results of the three Thanksgiving games have already been taken into account in the tables below.

Ranking Week 12 Games by Leverage

The table below ranks the week 12 games by total leverage. Leverage in this context is a measure of both how uncertain a game's outcome is (games between evenly matched teams have higher leverage) and how much the playoff picture swings as a result of that outcome.

Tuesday, November 24, 2015

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.

The sole week 11 pick was successful, with the Ravens just barely covering a 2.5 point spread (note: my point spread data comes from sportsdatabase.com).

Saturday, November 21, 2015

NFL Playoff Implications Week 11

Here are the playoff implications for the NFL's week 11 games. The purpose of this feature is to highlight games that have a significant impact on the playoff picture (see this post for background).

The playoff implications below are derived from a 50,000 round simulation of the remainder of the NFL season. I use my daily NFL rankings to simulate future games. I can group the simulation runs by the outcome of each game and then see how a team's playoff chances vary between the two groups. The interactive table at the bottom of the post will allow you to see corresponding results for any game or team.

Ranking Week 11 Games by Leverage

The table below ranks the week 10 games by total leverage. Leverage in this context is a measure of both how uncertain a game's outcome is (games between evenly matched teams have higher leverage) and how much the playoff picture swings as a result of that outcome.

Wednesday, November 18, 2015

Turnover Index Week 11

Here are the Turnover Index picks and results for week 11. 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.

The week 10 picks went 1-2 against the spread, but we eked out a net positive return. One of the losing bets, Seahawks over Cardinals, had just the slightest edge, and thus the Kelly criterion only dictated a small fraction of our bankroll to be bet.

Sunday, November 15, 2015

Live Ball vs Dead Ball Turnovers

Last season, I added a new feature to the site which allowed for a deeper dive into NBA team per possession efficiency. Per possession efficiency has long been a staple of advanced metrics. It allows for a more precise measure of offensive and defensive skill. While traditionally a box score stat, I used the detailed play by play data to break out efficiency based on how each possession began. With rare exceptions, a possession can begin in one of the following ways:
  • After an opponent made shot
  • After a defensive rebound
  • After a turnover
As one would expect, possessions after a turnover are the most efficient, due to their opportunities for fast breaks. However, several people pointed out that the turnover bucket includes both "live ball" turnovers (bad passes, steals, etc.) as well as "dead ball" turnovers (out of bounds, offensive fouls, etc.). If turnover efficiency is driven by fast break opportunities, then possessions off of dead ball turnovers should have a much lower efficiency than their live ball counterparts. Here are the results, aggregated over the past four full NBA seasons (2011-2014):

Saturday, November 14, 2015

NFL Playoff Implications Week 10

Here are the playoff implications for the NFL's week 10 games. The purpose of this feature is to highlight games that have a significant impact on the playoff picture (see this post for background).

The playoff implications below are derived from a 50,000 round simulation of the remainder of the NFL season. I use my daily NFL rankings to simulate future games. I can group the simulation runs by the outcome of each game and then see how a team's playoff chances vary between the two groups. The interactive table at the bottom of the post will allow you to see corresponding results for any game or team.

Ranking Week 10 Games by Leverage

The table below ranks the week 10 games by total leverage. Leverage in this context is a measure of both how uncertain a game's outcome is (games between evenly matched teams have higher leverage) and how much the playoff picture swings as a result of that outcome.

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.

Despite the week nine picks going 1-1 against the spread. we lost about 5% of our bankroll, due to the majority of funds being placed on the losing bet. The model had the underdog Cowboys to cover the three point spread at home against the Eagles. Dallas couldn't leave a perfectly good push alone, and kicked a field goal at the end of regulation to force overtime. The Eagles won the coin toss (or did they?) and scored a touchdown on their opening possession to win the game and, alas, cover the spread.

With the NFL's new overtime rules that prevent a team from winning with a field goal on their opening possession, one would think that the frequency of overtime games finishing with a six point margin (as opposed to 3 points) would increase. However, based on the 65 games that have gone to overtime since 2012 (when the rule change went into effect), the percentage of games ending with a six point margin is largely unchanged relative to pre-2012:

Sunday, November 8, 2015

NFL Playoff Implications Week 9

Unfortunately, weekly playoff implications will not be featured on FiveThirtyEight this season. But, I was able to dust off the code from the "classic" version I originally created for this site. It lacks the bells and whistles of the FiveThirtyEight version, but it gets the job done. The purpose of this feature is to highlight games that have a significant impact on the playoff picture (see this post for background).

The playoff implications below are derived from a 50,000 round simulation of the remainder of the NFL season. I use my daily NFL rankings to simulate future games. I can group the simulation runs by the outcome of each game and then see how a team's playoff chances vary between the two groups. The interactive table at the bottom of the post will allow you to see corresponding results for any game or team.

Ranking Week 9 Games by Leverage

The table below ranks the week 9 games by total leverage. Leverage in this context is a measure of both how uncertain a game's outcome is (games between evenly matched teams have higher leverage) and how much the playoff picture swings as a result of that outcome.

Wednesday, November 4, 2015

Turnover Index Week 9

In the week 7 writeup of the Turnover Index, I flagged the Jets as a team that may regress from its strong 4-1 start. Since that time, the Jets have dropped two straight. Granted, the first was to the undefeated Patriots, and the 2nd loss came after an early injury to starting quarterback Ryan Fitzpatrick.

But the most telling stat is defensive turnovers. Over their first five games, the Jets led the league in defensive turnovers, averaging three per game. In their two games since? Zero turnovers created on defense. It's only two games, but it makes for a nice illustration of the principle behind this betting strategy: turnovers "created" by the defense are largely random.

There were no week 8 bets, but there is one more correction to the historical results table (I promise this is the last one).