NBA Betting Against the Public 2003-10

  • Article: Betting Against the Public in the NBA (Based on 7 Seasons, ending June 2010)

We are entering a busy time for sports investors, with many of the major sports in action.  In addition to the most popular sports, the NFL and College Football — the sports with more frequent profit opportunities are getting underway, plus  the NHL is now in season.  Below, we update our analysis for “Betting Against the Public” in the NBA.  Our database now includes 7 seasons worth of data — and more than 9,000 games.  Most importantly, the results continue to show that “contrarian sports investing” can help put the “wind in your sails.”  Here, we highlight a bias of value on Visiting teams that the Public hates, something we have seen in the NHL as well.    

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SportsInsights Database and NBA Research

SportsInsights (SIs) has collected betting data for every major U.S. sport since the 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 trends percentages,”  Our research team also “cleans” our data — to ensure our historical data is useful for our research articles and our Members.  SIs’ historical database for each sport is an important part of our research and value-added for our Members.  It is the backbone for our contrarian sports investing  methods and you can’t find this kind of data and information anywhere else! 

Our database and contrarian methods are backed by tens of thousands of games across every major U.S. sport.  Data is available for seven major US sports — and may be purchased as a group — or for individual sports.  The SportsInsights NBA database now includes data going back to the 2003-04 season.  Here are some notes on the data that we used for this article:

  • Data for the past seven seasons (November 2003 through June 2010)
  • Includes the regular season and playoffs
  • Excludes pre-season and All-Star Games
  • More than 9,000 games.

Betting Against the Public — NBA

Over the years, SportsInsights’ proprietary “betting percentages” (obtained from actual sportsbooks) have proven to be a good contrarian sports investing tool.  Our Members can often find value by finding the most “lopsided bet” games of the day — and “Betting Against the Public.”  More specifically, if we see less than 25% of the bets on one team, it means that the public might be undervaluing that team.  There are very few games below the 20% level.

Table 1: NBA and Betting Against the Public (Last Seven Seasons, ending June 2010)

Betting % Win %
40% 50.5%
30% 50.1%
25% 49.8%
23% 49.2%

NBA Visitors Undervalued

The past several years of NBA data has shown that Visiting teams may be more undervalued than Home teams.  That is, if you “Bet Against the Public” and select only Visiting (or Away) teams (Table 2), your winning percentage would be higher than when both Visitors and Home teams are selected (Table 1, above).  The 53.0% winning percentage we bolded in the chart below is pretty solid — for a very simple system.

Table 2: NBA Visitors and Betting Against the Public (Last Seven Seasons, ending June 2010)

Betting % Win %
40% 52.1%
30% 52.7%
25% 53.0%
23% 51.5%

Summary prides itself in being an industry leader in sports information services.  We hope that you will make SportsInsights your one-stop shop for everything from live betting odds and scores to sports investing information — and betting systems.  Our Members enjoy some of the most innovative sports marketplace information available!  SportsInsights develops analytical tools that build upon sports marketplace indicators (such as “betting percentages” and “line moves”) to give our Members an edge over other handicappers.


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.