MLB Betting Against the Public Spring Training 2011 Article — MLB Spring Training Biases (March 2011)

Baseball’s spring training is underway.  As we get set for the 2011 Major League Baseball regular season, SportsInsights’ research analysts thought we would whet your appetite with several spring training betting tips.  The information below is based on thousands of MLB spring training games going back over the past six seasons.  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

SportsInsights (SIs) has collected betting data for every major U.S. sport since 2003.  We collect the opening and closing lines (and “line movement” for various sportsbooks), as well as final scores — and perhaps most importantly, SIs’ proprietary “betting percentages.”  SportsInsights’ database includes Major League Baseball going back to 2003 — and Spring Training data back to the 2005 season.

Spring Training Biases

Below, we summarize several betting biases that can be used if you are interested in betting spring training games. This includes SportsInsights’ “bread and butter” — “Betting Against the Public.”  As usual, SportsInsights stresses a contrarian “sports investing” philosophy and biases, such as seeking value and betting on underdogs.

We caution that, although these results are based on thousands of spring training games, this is a smaller sample size relative to our complete baseball database (which now covers almost 20,000 data points over eight seasons).  We are pleased, however, that the biases are similar to results we have seen in baseball’s regular season — as well as in other sports.

Betting on Home Underdogs

Similar to our MLB results during the regular season and playoffs, there is a bias for value on home teams.  In fact, this bias seems to be even stronger during spring training.  This may be due to the smaller sample size.  Some analysts also believe that during spring training, there are times when some players on the visiting team do not make a trip.  In any case, over the past several seasons, betting on home teams, that are underdogs, has resulted in profits.

  • Betting on a home underdog has resulted in +21 units (55% winning percentage)

Betting Against the Public on Home Teams

Our team of analysts also studied “betting percentages” during spring training — which appears to improve results for the home team bias.  Betting activity is much lower, as compared to the regular season, but the contrarian value that we have seen appear in baseball (value on home teams, plus contrarian value based on betting percentages) — also appears during spring training.  In particular, betting against the public on home teams has yielded solid profits over the past few years.

  • If the home team has less than 25.1% of the moneyline bets, betting on the home team has yielded +24 units (58% winning percentage)

Combination of Biases

By combining these biases (home underdog and “betting against the public”), you can increase your winning percentage and “return on investment.”

  • Betting on home underdogs with less than 25.1% of the moneyline bets results in +10 units (60% winning percentage).


Value, based on an academic approach to “betting against the public” can yield a real edge in sports investing.  Stay tuned for SportsInsights’ latest addition to our series of articles on “betting against the public” — in Major League Baseball.  Baseball has been one of our most consistent sports:

SportsInsights’ MLB Square Plays have been profitable since inception, winning in 6 of 7 seasons, and earning +39 units, +39 units, and +21 units over the past three seasons.  

Year Units
2010 +24.43
2009 +38.98
2008 +38.78
2007 +14.67
2006 -15.89
2005 +6.29
2004 +20.63
Overall +127.89


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.