Wednesday, November 28, 2012

The Turnover Index - Week 13

Here are the Turnover Index numbers for Week 13 of the NFL season.  The purpose of these weekly posts is to find betting opportunities that exploit the market's tendency to overvalue a team's season to date defensive turnovers.  See here and here for more background.

Last week's picks just went 1-2 against the spread.  The Rams covered in their game against the Cardinals, but the Vikings and Packers failed to cover in their respective matchups against the Bears and Giants.

Tuesday, November 27, 2012

Betting Market Analytics vs. The Linemakers

While googling line predictions for the BCS Title game for this post, I stumbled across a section of the Sporting News called The Linemakers.  They have a power ratings section that appears to be doing the same thing I'm attempting with my rankings.  Here is the description from the site:

"Power Ratings are numerical values assigned to teams that intend to provide the basis for what the spread should be between two teams at a neutral site. They are updated every week during the season."

That could function as a description of my rankings as well.  To be honest, I don't how they derive the rankings at that site, but I figured I would put their rankings and mine to the test and see which set was best at predicting how the market sets the point spreads for upcoming games.

Sunday, November 25, 2012

BCS Title Game - Line Predictions

With the BCS Title Game scenarios now down to Georgia-Notre Dame or Alabama-Notre Dame, here are predictions of what the point spread and over/under would be for both potential matchups, using my betting market rankings.

The Ticker - NBA and NFL Versions Now Available

The Ticker is now available for both the 2012 NFL season and the 2012-2013 NBA season.  The Ticker is a feature I first launched for the NBA back in March of this year.  The purpose of this feature is to display how each team's Generic Points Favored (GPF) has changed as the season has progressed.  My GPF ranking can be thought of (almost literally) as the stock price of a team, so the Ticker tracks that movement over time, as a standard stock ticker would.

NFL

I just have one chart for the NFL, displaying total team GPF.  As you can see, the movement is fairly noisy from day to day, but some overall patterns are fairly clear.  You can see how the market's faith in Arizona has slowly bled away over the past two months.  Or how Denver's stock has continued to rise as Peyton Manning has put to rest any doubts about his ability to return from injury.

NBA

There are three charts for the NBA:
  • GPF - Same as the NFL, an area chart showing day to day movement in team Generic Points Favored.  It's pretty early in the season, so there's not a whole lot of movement.
  • GPF+oGPF+dGPF - This chart displays team GPF along with its offensive and defensive components: oGPF and dGPF.
  • GOU - Stands for Generic Over/Under.  This is what you would expect the betting over/under to be when playing a league average team.  This is a function of offense, defense, and pace.  For comparison, the graph also displays the league average over/under (AOU).


NFL Scoring Margin Distributions

This is a follow up from my previous post on building an in-game cover probability model for the NFL.  As a first step in that process, I calculated an expected scoring distribution for any given point spread.  I derived this by building an ordered logistic model off of actual NFL scores, with the Vegas point spread as my independent variable.  In that original post, I shared the expected distribution for a 7 point favorite.  The tool below will provide the distribution for any point spread (from 0 points to 21 points).

Saturday, November 24, 2012

NBA Team Rankings Now Available

NBA team rankings are now available for the 2012 season.  For those of you unfamiliar with my ranking methodology, the goal is to reverse engineer an implied power ranking from the Vegas point spreads.  I'm trying to figure out who the betting market "thinks" are the best teams in the league.  In addition, by combining the point spread with the betting over/under, I can decompose team strength into its offensive and defensive components.  My Methodology page has a simple example of how the rankings work.  You can also refer to my series of posts at Advanced NFL Stats Community, where I first created these for the NFL.

Here is a direct link to the ranking table.  As with my NFL, NCAAF, and MLB rankings, these update every morning with the latest game results and betting information.  My source is Sportsdatabase.com.

Friday, November 23, 2012

In-Game Cover Probability: A Start

This is the first post in what I hope to be a series on the topic of in-game cover probability.  I view the idea as an extension of the Win Probability graphs at Advanced NFL Stats.  For those of you not familiar with the win probability graphs, the general idea is to estimate a team's chances of winning a game given down, distance to go, field position, time remaining, and point differential.  As I understand it, the probabilities are not derived from a Madden-style simulation, but are rather based on actual game outcomes, with some LOWESS smoothing to fill in the gaps where there isn't sufficient data.

What I hope to explore here is whether a similar model can be built to determine a team's probability of covering the spread.  As an example, take the week 7 matchup between Chicago and Detroit.  With about 40 seconds to go in the game, Detroit trailed by 13, but had the ball on the Chicago 12.  The ANS probability model gave Detroit a 1% chance of winning the game at this point, so not a lot of drama, unless you had bet on the spread.  Detroit was a 6.5 point underdog.  A touchdown by Detroit would put the margin at 6 points and Detroit would cover the spread.

Tuesday, November 20, 2012

The Turnover Index - Week 12

Here are the Turnover Index numbers for Week 12 of the NFL season.  The purpose of these weekly posts is to find betting opportunities that exploit the market's tendency to overvalue a team's season to date defensive turnovers.  See here and here for more background.

Last week's picks went 1-1 against the spread.  The Bears-49ers game was a perfect example of what these posts intend to illustrate: The Bears, despite having averaged 3.3 defensive turnovers per game and facing a QB making his first NFL start, could not generate a single turnover.  Regression to the mean in action.

Wednesday, November 14, 2012

The Turnover Index - Week 11

Here are the Turnover Index numbers for Week 11 of the NFL season.  The purpose of these weekly posts is to find betting opportunities by exploiting the market's tendency to overvalue a team's season to date defensive turnovers when evaluating future performance.  See here and here for more background.

Last week's picks went 2-0 against the spread.  Cincinnati covered the spread (and then some) in their matchup against the Giants.  The Giants managed to force only one turnover, despite having averaged about 3 per game for the season.  The Bears failed to cover the spread against the Texans, having lost Jay Cutler to a concussion midway through the game.  Chicago forced two turnovers in the game, which is above the league average of 1.6, but below their season-to-date average of 3.5.

Wednesday, November 7, 2012

The Turnover Index - Week 10

Here are the Turnover Index numbers for Week 10 of the NFL season.  The purpose of these weekly posts is to find betting opportunities by exploiting the market's tendency to overvalue a team's season to date defensive turnovers when evaluating future performance.  See here and here for more background.

The Bears - 28 Turnovers in 8 Games

Before getting to the Week 10 numbers, I wanted to take a look at the Bears and their impressive turnover performance thus far this season.  In their first 8 games, the Bears have generated (received?) 28 defensive turnovers.  Going back to 1998, only the 2005 Bengals managed more turnovers (29) in the same amount of time.  See the table below for the outcomes for all teams that managed at least 24 defensive turnovers in their first 8 games:

Monday, November 5, 2012

Ranking Table - Mouseovers

In my ongoing effort to crowd 10 pounds of data into a 5 pound bag, I've added some mouseovers to my NFL and NCAA Football rankings that provide additional layers of drill-down for the numbers I'm reporting.

NFL Tables

  • Last Week - If you mouse over the "LstWk" sparkline for each team, you'll see the actual daily GPF (Generic Points Favored) numbers for the team going back 7 days.
  • Projected Wins - Mouse over the bar graph for the numerical win total probabilities.  For example, as of November 5, the Falcons have a 3% chance of going 16-0 in the regular season, according to my simulations.
  • Strength of Schedule - The SOS columns on the far right summarize the average GPF of each team's opponents, split by opponents already faced and opponents remaining on the schedule.  Mouse over the number for the week by week detail.  As an example, the Broncos have the easiest remaining schedule as of November 5, with an opponent average GPF of -2.3 points.  Mousing over that number shows that only one of Denver's remaining 8 games comes against a team with an above average GPF.