MLB Betting Against the Public 2007 Midseason Review Article — MLB and Seasonal Biases when Betting Against the Public (Includes 2003-07 Seasons)

The 2008 Baseball Season has gotten off to a positive start for’s strategies.  Thanks to the suggestion of some of our Members, SI’s researchers took a look at how “Betting Against the Public” fares during various parts of the season.  Do we always do particularly well during the early part of the season?  What about near the end of the season — when teams are driving for the playoffs?  With more than 11,000 data points over five seasons, baseball shows robust results throughout the season and impressive statistical results for the entire data set.  The information on this site is for entertainment and educational purposes only. Use of this information in violation of any federal, state, or local laws is prohibited.

MLB Database (2003-2007 Seasons)

SportsInsights’ database for MLB now includes over 11,000 games over the past five seasons.  For the purposes of this article, we include the playoffs, but exclude spring training.  Similar to hockey, baseball is a “moneyline” sport, so that we emphasize “units won” (and not winning percentage).  For the purposes of this study, we split the season into three sections, as follows:

  • Early part of season: Before June 1 (excludes Spring Training)
  • Middle of season: June and July
  • End of season: After July 31 (includes Playoffs).

Betting Against the Public during the Season

Our regular “MLB – Betting Against the Public” article, published a few weeks ago, shows that fading “Joe Public” at the 30% level yielded +131 units over the past five seasons.  Here is how the results look — broken down by “part of the season.”

Table 1: MLB and Betting Against the Public Broken Down by Part of Season

(2003-2007 Seasons)

Betting % Threshold Early Season(Before June) Middle of Season(June, July) End of Season(After July) Total
30 +3 +103 +25 +131

Using the Table

  • You can see that the results match up with our results of +131 units at the 30% “Bet Against” level (includes both Home and Visiting teams).
  • Each period yields positive results.  However, it seems like the middle part of the season yields the best results overall.
  • We would caution against focusing your attention on only the middle portion of the season.  While the data highlights June and July for this strategy, there is a correspondingly lower number of data points during these months (versus the entire data set).  For example, if you decided to wait until June to start “Betting Against the Public,” you would have forfeited the +10 units that SportsInsights’ MLB Square Plays have yielded so far this season.
  • SportsInsights’ betting systems have both historical data and fundamental reasons (such as “contrarian value”) on its side.  We can’t tell when the sports investing approaches will get “hot or cold” — but we believe they will earn profits in the long run.

Some Notes

  • Again, we want to emphasize that conclusions from this article should be taken with a grain of salt.  Results are based on correspondingly fewer data points as we split data into several groups.
  • This being said, we would like to highlight some additional points:
    • – Interestingly, visiting teams performed better than home teams (gained more units) near the end of the season.
    • – Home teams gained more units than visitors during the early part of the season.

Good luck — and keep your emails and comments coming.

We do not guarantee that the trends and biases we’ve found will continue to exist. It is impossible to predict the future. Any serious academic research in the field of “market efficiencies” recognizes that inefficiencies may disappear over time. Once inefficiencies are discovered, it is only a matter of time before the market corrects itself. We do not guarantee our data is error-free. However, we’ve tried our best to make sure every score and percentage is correct.