Wednesday, December 19, 2012

Turnover Index - Week 16

Here are the Turnover Index numbers for Week 16 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.

Week 15 Performance

Results were once again split for week 15, going 3-3 against the spread.

Turnover Index through Week 15 (Against the Spread): 17-13-1

Overall, that is 56% against the spread.  Still above the breakeven point of 52.4%, but definitely a drop off from the high water mark of 67% we saw after week 11.

Regression, Randomness, and Bears

My week 10 post focused on the Bears and their (at the time) league-leading defensive turnovers.  Based on prior seasons, most teams that had achieved that level of turnovers were not able to sustain that performance for the remainder of the season.  Through eight games, the Bears had averaged 3.5 defensive turnovers per game, won 7 of 8, and were 5-2-1 against the spread.  Over the next 6 games, the Bears averaged 1.5 turnovers per game, lost 5 of 6, and went 1-5 against the spread.

Week 16 Picks

There are four betting opportunities this week.  As a reminder, the criterion we use is any game in which there is at least a 10 defensive turnover differential between the two teams.  We bet on the team with the lower amount of turnovers.  See the table at the bottom of the post for the details.

  • New England @ Jacksonville - Pick: Jacksonville
  • Washington @ Philadelphia - Pick: Philadelphia
  • Cincinnati @ Pittsburgh - Pick: Pittsburgh
  • Atlanta @ Detroit - Pick: Detroit

Here is the complete table of matchups:


  1. Where are you getting the lines? I've usually seen SF as the favorite by 1.

    Also, 3 of your four picks are teams that are no longer in playoff contention against teams that are. I'm trying to reconcile that with the predictions -- any thoughts?

    My picks for the week: (Currently 69-52-6)
    New Orleans +3
    Washington -4.5
    Cincinnati +4
    Tampa Bay -3
    Oakland +8.5
    Houston -7.5
    Seattle (2 units) 0.0

    1. My source is (there's a link at the top of the rankings page). According to SBRForum, there are sportsbooks with SF as a 1 point favorite and others with the game as a pick'em.

      On your playoff contention comment, I'm assuming that the spread factors motivation/roster experiments into the point spread, but that the underlying starting point for that point spread is still skewed by turnover performance.

    2. So, New Orleans, Washington, Cincinnati, and Seattle Covered, putting me at 5-3 for the week. 74-55-6 - right at the 57% I expected to see.

      I ran a betting simulation. At full Kelly, I'd have lost 7.5% of my bankroll. At half kelly, I'm up 5.6%. Some pretty brutal swings in there.

  2. Forgot the Giants -2.5

    1. That should have been no bet - like it originally was - since they're @ the Ravens. Next time I count with my fingers.

  3. what are your picks based on Nate?

  4. I believe the spread misjudges home field advantage. There's more elaboration on the Week 14 Turnover Index post.

  5. It looks like roughly 1 in 10 turnovers is run in for a touchdown, which seems to match up to the 10 turnover differential in the index. I need to redo my work, but my initial survey indicates that teams tend to loose against the spread significantly in games after they get a turnover touchdown.