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Why You Should Look At Underdogs In NFL Preseason

I sat watching a replay of the Miami Dolphins-New York Giants with OddsShark’s newest host, Alex Haider, on Monday morning and was quickly reminded how difficult it is to stomach NFL preseason football. 

But Associate Finance Professor Kevin Krieger from the University of West Florida has me rethinking things. 

Krieger recently co-authored a paper “Preseason bias in the NFL and NBA betting markets” and what the research uncovered will definitely make you think a little harder about your wagering action this August in football. 

“Underdogs cover disproportionately in preseason games,” says Krieger.  “The biggest headline (from this study) is, very naively betting all underdogs, you’ve covered the juice for 20 years. And if you ignore Week 3, betting the same amount every game, you’ve been ahead for 20 years.” 

Krieger’s paper shows that underdogs have hit at almost exactly 52.4 percent in the NFL preseason over the last 20 years - which just happens to be the winning rate you need to cover at in order to turn a profit using the standard -110 price tag on most point spread bets. 

It gets even better if you avoid Week 3 where the underdog cover rate goes up to 53.3 percent based on 900 NFL preseason games over 20 years.   

Obviously this formula doesn’t work out perfectly in every season but it did in 14 of the last 20 years. And it’s noteworthy because (frustratingly) favorites and underdogs almost always work out to a 50-50 record against the spread in every NFL season. Oddsmakers are just that good. 

“Avoid Week 3 (in terms of betting teams blindly) since you have a lot of teams playing starters for considerably more of each game,” says Krieger.  

The good news for bettors is the numbers get even better when you look at bigger point spreads. Here’s a look at the cover rate for spreads of +3.5 points and higher and also +5.5 points and higher. 

Underdog ATS performance in NFL preseason (LAST 20 years)
PointspreadATS Win Rate For All WeeksATS Win Rate Excluding Week 3Sample Size
+3.5 or higher53.2%54.1%385 games
+5.5 or higher57.7%61.7%133 games

In short, the bigger the dog the louder it barks when it comes to the NFL preseason. 

According to OddsShark’s closing lines, underdogs of 3.5 points or more are 2-2 against the spread this preseason and we haven’t had a line yet of higher than 5.5 points. The closest was the Dallas Cowboys were 5-point underdogs to the L.A. Rams last week and covered by one point in a 28-24 loss. 

Still, there’s plenty of preseason left and now you have the numbers that show it’s probably not a bad idea to keep a close eye on the bigger underdogs as games roll on. 

“We did this to try to better understand why people make the mistakes that they make and handicapped games are a fantastic vehicle to play that out because the results are very cut and dried,” says Krieger. “Somebody covers and somebody doesn’t and it makes the grading and the way to evaluate very easy after the fact how correct the pricing seems to be.”