Predicting Season Win Totals, part IIThanks to our friends at Americasline.com, we were able to get our hands on the season win over/under lines for the five years from 1996 to 2000, and then we have added in our own results from the 2001 thru 2007 campaigns. Consequently we can provide a twelve-year look at this bet type! The first breakout to consider is simply how have teams done at certain "win lines" (for example how often have teams with a line of 8 go over versus under the number).However, there is one thing to note with these results -- with the emergence of the offshore industry we have seen the bet type move to being frequently posted on 1/2 win numbers (to avoid the commonplace pushes on whole numbers) with a money line adjustment. As a result there are few new whole number cases, and the scheme really needs to be changed to reflect the prices on the totals, not just the straight W-L outcomes. With help from Bodoglife.com we should shortly be able to factor in prices on the lines.
Team Seasons where the season wins equal the line (push bets) are ignored ANALYSIS: All lines used in compiling the above table were "current" rather than opening ones, taken from close to the start of the season and presumably after most of the line moves had taken place. It's important to be cautious when looking at small samples of data to NOT jump to conclusions. For instance, looking at the above it would seem that teams with adjusted season win lines (after significant betting activity) of 6 or fewer wins might be good OVER plays at 28-15 over the last twelve years, but that's not a huge sample, although a clear trend. Likewise, teams with high adjusted win lines of 9 1/2 or more wins have done poorly, and as a result have gone 60-34 as UNDER plays, but it's again falling short of being completely significant. Still, the history has been that there is potential value at "both ends" of the table. Another consideration is how a team's prior year record compares to the line set for them this season (for example if a team was 6-10 last year but has a season win line of 8 1/2 this year, then they would count as a +2 1/2 on the "Net vs Line"):
ANALYSIS: While we are still stuck with our limited sample size, once more the extremes of the table are interesting. Teams with season win lines of 3 games or more BELOW their previous year's win total have gone 12-3 as UNDER plays. Meanwhile teams with season win lines of 3 games or more ABOVE their previous year total are 17-10 as OVER plays.
Or, to look at a larger grouping, when a team's season win line is 1.5 plus games below their prior year win total, such teams have gone 50-27 as UNDER plays, while teams with a line 1.5 games or more above their previous win tally are 64-43 as OVER plays.
This suggests that the season win lines may perhaps not reflect the true levels of improvement/decline expected with these dramatic cases -- understandable when you think bettors are already having to come to terms with a line of say 9 wins on a team that was 6-10 (or worse) in the previous year!
An even bigger view is to note that teams projected to have the same or worse record (0 to -3 or below) are 105-74 (59%) as under bets all told, while teams expected to improve by at least half a game are 102-76 (57%) as overs. In general then the line doesn't move far enough to represent the changes in the offseason.
ANALYSIS: These numbers are quite revealing. The optimal conditions for a "bounce" are when a team has shown a dramatic change in performance and the theory goes (for many reasons) that the next performance will revert closer to the norm. Well, for NFL squads that jumped up by 3 or more games in the prior year, they have gone 58-35 as UNDER plays in the following season, whereas NFL teams that were 3 or more games worse in the last season are 57-33 as OVER plays.
So the Bounce Theory is confirmed: teams with dramatic changes from one season to the next in total wins do tend to revert in the subsequent year, at least in so far as versus the season win total expectancy placed on them by the linemakers.
All of the three above tables give us some grounds to make predictions going forward, but none should be construed as a full scale analysis of how to play the season win numbers alone, for that we recommend a multi-factor look at delving deeper...and we will! The official (subscriber only) TMW picks will be posted soon!
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