Give a casual bettor the option of wagering on a team with a winning record or a team with a losing record and they’ll put their money on the good team every time.

Since 2005, there have been 6,867 games in the NBA featuring a team with a winning record against a below .500 squad. In 86.1% of those matchups, recreational bettors sided with the winning crew.

On Saturday, the Boston Celtics (14-2) travel to Atlanta for a game against the Hawks (3-12). Guess which team will receive the majority of spread tickets? The C’s have won 14 straight and rallied from down 17 points against the defending NBA champion Golden State Warriors on Thursday night.

Lines are not available, keep checking the free odds page from Sports Insights for updates, but it would be fair to assume that casual bettors will be on the Celtics. Historically, great teams are overvalued when they hit the court against the league’s worst units.

We’ll call this the 70-70 rule. If a team that has won more than 70% of their games plays a team that has lost greater than 70% of its contests, fade the winning team. Since 2005, betting against the winning team is 347-274-11 (55.9%) ATS in these matchups.

You can improve the betting system by adding almost any filter:

  • Winning team is on the road: 189-146-3 (56.4%) ATS
  • Winning team won previous game: 294-209-10 (58.4%) ATS
  • Winning team covered previous game: 222-148-8 (60.0%) ATS

Boston will likely win its 15th straight game on Saturday but the Celtics are going to be overvalued by the public. Contrarian bettors can profit by taking the Hawks and an inflated line. Of course we recommended betting against the C’s when they played the Nets on Tuesday and the Warriors on Thursday, neither worked out. Two games is not meaningful, we have a 600 game sample size that says good teams are bad bets when they play the worst teams in the league.

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