I have heard this argument in many circles that are trusted. The hypothesis goes like this. Vegas knows that the average gambler plays mostly favorites so the lines are slanted to get the Smart Money to play the Underdog to even it out. The argument makes sense that Smart bettors only play dogs. Is playing just Underdogs the way to go?

Let’s take a close look. When I was doing the article on How many Underdogs win outright, I decided to look at how the Underdogs do vs the spread.

Here is the chart of every underdog since 1997, a 24 year span.

I plugged in every game since 1997 which is 17,869 games. If you blindly played the Underdog on each game you would have a record of 8874-8725-270  for a winning percentage of just 50.4%. To make money wagering on sports you need to win 52.5% of the time just to break even after you deduct the juice. Over the last 24 years the statement that you should only bet Underdogs is FALSE.

No let’s take a look at last 10 years results.

 

I plugged in every game over the last 10 years I plugged in every game the last 10 years which is 8241 games. If you blindly played the Underdog on each game you would have a record of 4094-4015-132  for a winning percentage of just 50.5%. To make money wagering on sports you need to win 52.5% of the time just to break even after you deduct the juice. Over the last 10 years the statement that you should only bet Underdogs is FALSE.

Can we find any spots where playing the Underdog does work out? Only TWO of the 14 categories produced a record above 52.5% but they do not come along very often. Over the last 10 years teams that were a 49.5 underdog or higher do have a record of 39-21-1 for a 64.9% winning record. So if a team is getting over 7 TD’s then go ahead, blindly play the underdog but other than that it is basically a 50/50 proposition.

Final Answer: The statement you should only bet underdogs is FALSE