Saturday, December 27, 2014

Transitive College Football Power Rankings - Bowl Games Edition

Three paths from A to BIn a recent post (My Team's Proxy Can Beat Up Your Team's Proxy), I laid out an approach for comparing two college football teams (or two teams from any sport, really). The original version allowed the user to compare any two top 25 teams. For this post, I have created a Bowl Games version which automatically generates these comparisons for every Bowl Game matchup of the season. The basic idea is to generate comparisons by trying to connect teams via "paths". We find our paths by looking at prior game results.

For example, the Alabama Crimson Tide play the Ohio State Buckeyes on New Years Day in the first round of the College Football Playoffs. These two teams have not played each other this season, so there are no direct paths connecting them. In addition, they do not have any common opponents, so there are no paths of length two connecting them either. But some of their opponents have played each other, so there are paths of length three available:

Wednesday, December 17, 2014

Turnover Index - Week 16

Here are the Turnover Index picks for Week 16. 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.

Week 14 results

Our week 14 bet was successful against the spread, with the Raiders covering against the Niners. Here are the season to date results:
  • Against the Spread: 8-2
  • Starting Bankroll: $1,000
  • Current Bankroll: $1,073 (8% ROI)
And here are the week by week results:

weekbetswonstarting
bankroll
amount betprofitsending
bankroll
7 2 2 $1,000 $51 (5.2%) $47 $1,047
8 2 1 $1,047 $26 (2.6%) $1 $1,048
10 2 2 $1,048 $32 (3.1%) $29 $1,077
12 2 1 $1,077 $26 (2.5%) ($11) $1,066
13 1 1 $1,066 $7 (0.7%) $6 $1,073
14 1 1 $1,073 $6 (0.6%) $5 $1,079

Week 16 Playoff Implications

Week 16 playoff implications are now available at FiveThirtyEight. This week, the "best case" interactive has been upgraded with a "top pick" button, giving fans of the Buccaneers and the Titans something to do besides sob quietly. For determining draft order, the first tiebreaker is strength of schedule, which leads to some interesting implications for Tampa Bay and Tennessee. Their list of "rooting interest" games is extensive.

UPDATE 2014-12-21: As now called out in the article, there was an error in the tiebreaker logic that led to incorrect probabilities for the top seed and bye week probabilities in the NFC. This has now been corrected. The programming error was 100% my own.

Saturday, December 6, 2014

Turnover Index - Week 14

Here are the Turnover Index picks for Week 14. 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.

Week 13 results

Our week 13 bet was successful against the spread (the Jets covered against Miami in a losing effort). Here are the season to date results:
  • Against the Spread: 7-2
  • Starting Bankroll: $1,000
  • Current Bankroll: $1,073 (7% ROI)
And here are the week by week results:

weekbetswonstarting
bankroll
amount betprofitsending
bankroll
7 2 2 $1,000 $51 (5.2%) $47 $1,047
8 2 1 $1,047 $26 (2.6%) $1 $1,048
10 2 2 $1,048 $32 (3.1%) $29 $1,077
12 2 1 $1,077 $26 (2.5%) ($11) $1,066
13 1 1 $1,066 $7 (0.7%) $6 $1,073

Thursday, December 4, 2014

My Team's Proxy Can Beat Up Your Team's Proxy

In a few days, the College Football Playoff Selection Committee will release their final team rankings. The committee ranks the top 25 teams in the nation, but it's the top four that everyone will pay attention to.

As a public service/argument starter, I have created a comparison tool for any two teams currently ranked in the top 25 by the Selection Committee. The purpose of this tool is to find "connections" between the two teams, with the goal of determining which of the two is superior.

The basic idea is to view the combined output of all college football games as a map. But the terrain we are mapping has some peculiar and inconsistent topology. Let's take the week 12 matchup between Alabama and Mississippi State. Alabama won that game by five points. One way to interpret that is to say that Alabama is five points "better" than Mississippi State. Or, to use our map analogy, "Mount Alabama" is 5 points higher in elevation than "Mount Mississippi State".

Week 14 Playoff Implications

Week 14 Playoff Implications are now up at FiveThirtyEight. Reuben Fischer-Baum has added yet another nifty interactive to our weekly feature. This one tells you which games are most important to any given team (note that the probabilities aren't independent so they only add approximately). The most important game this week is between the Ravens and the Dolphins. The winner emerges with a 70% playoff probability. The loser drops below 20%.