How Does the Number of Bets Impact MLB Contrarian Betting?

How Does the Number of Bets Impact MLB Contrarian Betting?

At Sports Insights, we constantly advocate the importance of implementing a contrarian betting strategy. By going against the mainstream narrative and taking unpopular viewpoints, bettors have been able to capitalize on market inefficiencies and exploit public perception. Casual bettors love betting favorites and overs, so sportsbooks will shade their opening lines to account for the inevitable influx of public money. This has historically created value on underdogs and unders.

We have conclusively proven that betting against the public will produce a positive return on investment, but the optimal threshold varies greatly from sport to sport. In the most recent MLB Betting Against the Public Report, I explained that underdogs receiving less than 30% of moneyline tickets have been very profitable — particularly in divisional games with high totals. By utilizing sharp money indicators like reverse line movement, contrarian bettors have been able to maximize their profits.

In the past, I have proven that the value derived from betting against the public is directly correlated with the number of bets placed on each game. That’s particularly in college sports where the number of bets varies greatly from game to game. A marquee matchup like Duke-North Carolina will attract tons of action from casual bettors, and one-sided public betting will often cause oddsmakers to adjust their lines to minimize risk. However, a small conference matchup will receive limited action, and oddsmakers have no incentive to adjust their lines based on one-sided public betting since there’s so little liability.

For the most part, balanced books are a myth and oddsmakers are willing to have liability if they believe they’re on the right side. Sportsbooks aren’t in the business of minimizing risk; they’re in the business of maximizing profits. That means sportsbooks won’t adjust their number based on public betting unless there’s massive liability on one side. The truth is that sportsbooks shade their opening lines to capitalize on public perception and allow their most-respected clients to shape the line.

Although sportsbooks mainly cater to their sharpest bettors, public money still factors into MLB line movement. “[Public money] plays more of a role than most sports because of the sheer volume of games,” said Scott Cooley, a spokesman for “The sharps aren’t involved in every matchup every night, so when they aren’t, we’ll adjust the numbers if we’ve got too great of public exposure on one side. Also, since we’re mostly dealing with moneylines we can adjust for public action in small increments.”

By jumping on moneylines that have been artificially inflated based on public betting, contrarian bettors can consistently realize added value. Although MLB betting volume doesn’t have the same level of variance as we’ve observed in college basketball or college football, we have still found that it’s more profitable to fade the public in heavily bet games. Over the course of a 162-game regular season, oddsmakers become increasingly willing to adjust based on public money in heavily bet games with one-sided public betting.

Using our historical database, I wanted to examine how betting against the public has performed in smaller games (fewer bets than the daily average) as compared to heavily bet games (more bet than the daily average). The table below grades the performance of betting against the public based on closing lines at Pinnacle.

Public BettingRecord (Small)Units (Small)ROI (Small)Record (Big)Units (Big)ROI (Big)
<50% of ML bets6996-8349-169.04-1.1%5763-7659-162.60-1.2%
<40% of ML bets4150-5338-116.51-1.2%4336-6117-136.41-1.3%
<35% of ML bets2910-3875-71.30-1.1%3623-5152-13.67-0.2%
<30% of ML bets1774-2469-49.16-1.2%2808-4027+61.47+0.9%
<25% of ML bets870-1314-70.48-3.2%1783-2690-12.98-0.3%
<20% of ML bets289-440-15.82-2.2%900-1346+52.40+2.3%

Blindly betting against the public isn’t necessarily an effective strategy, which is why our annual betting against the public support considers additional trends when determining the sweet spot for contrarian betting. That said, it’s clear that betting against the public is a much more effective strategy in heavily bet games — especially in games with extremely one-sided public betting. Teams receiving less than 30% of moneyline tickets have produced a -1.2% return on investment (ROI) in smaller games and a +0.9% ROI in heavily bet games.

As noted in an earlier article, the Pinnacle MLB steam move has been incredibly profitable for bettors and it’s one of the best identifiers of sharp money. Since sportsbooks will only adjust their lines based on one-sided public betting in games where sharp money isn’t involved, I wanted to examine the same contrarian strategies when no Pinnacle steam moves had been triggered on the public side. This simple addition led to improved returns at almost every data point.

Public BettingRecord (Small)Units (Small)ROI (Small)Record (Big)Units (Big)ROI (Big)
<50% of ML bets6218-7318-87.00-0.6%5125-6687-47.07-0.4%
<40% of ML bets3682-4677-65.50-0.8%3869-5384-64.53-0.7%
<35% of ML bets2592-3388-10.95-0.2%3241-4533+48.91+0.6%
<30% of ML bets1592-2174-8.09-0.2%2516-3559+93.95+1.5%
<25% of ML bets784-1140-20.60-1.1%1602-2383+9.26+0.2%
<20% of ML bets261-384-1.81-0.3%785-1178+38.12+1.9%

When there hasn’t been a Pinnacle steam move triggered on the public side, teams receiving less than 30% of moneyline tickets have produced a -0.2% ROI in smaller games and a 1.5% ROI in heavily bet games. Identifying heavily bet games with one-sided public betting and limited sharp involvement is an ideal strategy for contrarian bettors, but there are many other factors that need to be considered when handicapping games.

The number of bets statistic is proprietary Sports Insights information that is available exclusively to Sportsbook Insider subscribers. Sign up for a 4-day Pro trial and you will also receive real-time odds, public betting trends, money percentages, e-mail alerts, our in-house Best Bet picks and much more.

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David Solar

David was the Content Manager at Sports Insights. He has since moved on to greener pastures.

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