3 Tips for Understanding the True Chances of an Underdog

Throughout the history of major sporting events across the globe, many so-called underdogs have achieved almost the impossible and won an event that nobody would have expected them to before the event started. The underdog is the least favorite to win an event.

While I do tend to avoid placing bets on the underdogs, I must admit, I do still place them on certain sporting events, and on one occasion, I did actually win a tidy profit from a relatively small bet.

Underdogs are also commonly referred to as longshots or outsiders because they have ‘long’ odds and low implied probability rates. In other words, the chances of them being triumphant (i.e., the IPR or implied probability rate) based on the odds they are priced at tell us that they aren’t worth betting on.

However, history has taught us on many occasions that underdogs do sometimes win. With that said, here are three essential tips for better understanding the chances of an underdog winning.

Is There Always an Underdog?

For almost every sporting event, there will always be an underdog, whether it’s a horse race with 25 runners, a football match with only two teams, or a boxing match with two fighters.

However, sometimes, the teams/individuals you want to bet on might be evenly priced. Most of the time, I would say there is always a clear favorite.

For example, in an English Premier League football match between Manchester City and Arsenal, two evenly matched teams, you might be looking at 11/10 fractional odds for Manchester City to win and 23/20 for Arsenal to win.

This means that the slight odds-on favorites, Manchester City, have a 47.60% implied probability rate of winning this match, compared to Arsenal’s 46.50% implied probability rate. Here’s a different way of looking at it:

  • Bet type: Manchester City will beat Arsenal outright. Fractional odds: 11/10. Decimal odds: 2.10. American/moneyline odds: +110. IPR: 47.60%
  • Bet type: Arsenal will beat Manchester City outright. Fractional odds: 23/20. Decimal odds: 2.15. American/moneyline odds: +115. IPR: 46.50%

In other words, although Arsenal is the ‘underdogs’ in this match, the odds are still fairly evenly priced, meaning Arsenal could easily upset the odds to win this event. The implied probability rate will always be the same for any odds format you choose.

Is it the Same in Horse Racing?

Yes. The same principles apply to horse racing, except in this sport, I’ve found that it’s much easier to see who the underdog is. Here is a quick example:

  • Bet type: Outright class 1 Flat race winner in the 14:25 at Newmarket racecourse. Horse: Babouche. Fractional odds: 7/4. Decimal odds: 2.75. American/moneyline odds: +175. IPR: 36.40%
  • Bet type: Outright class 1 Flat race winner in the 14:25 at Newmarket racecourse. Horse: Lake Victoria. Fractional odds: 9/4. Decimal odds: 3.25. American/moneyline odds: +225. IPR: 30.80%
  • Bet type: Outright class 1 Flat race winner in the 14:25 at Newmarket racecourse. Horse: Daylight. Fractional odds: 11/4. Decimal odds: 3.75. American/moneyline odds: +275. IPR: 26.70%
  • Bet type: Outright class 1 Flat race winner in the 14:25 at Newmarket racecourse. Horse: Magic Mild. Fractional odds: 66/1. Decimal odds: 1.50. American/moneyline odds: +6,600. IPR: 1.50%

As you can see, the clear underdog in this race is Magic Mild at 66/1. Some of the most famous examples I can give you where the underdogs (least favorite horses) have upset the odds are 2013’s Auroras Encore, which was priced at 66/1 and won the UK Grand National at Aintree racecourse.

In 2009, Mon Mone won at 100/1, and Last Suspect won at 50/1 in 1985, and in football, underdogs Leicester City achieved the impossible and won the English Premier League in 2015/16.

Some people bet on them at the start of the season to win the Premier League outright before the season started, and while they were priced on most sites at 5,000/1. Mastering the art of winning underdog bets like this is something that very few people learn and usually boils down to pure luck when they do place those types of bets.

Several people won big on Leicester, and it changed how sports betting operators priced up the underdogs pre-season.

For example, today, you will never see teams priced at 5,000/1 at the start of the season to win the Premier League outright, more like 2,500/1, because Leicester City has proved that even the underdogs can win.

3 Ways to Identify the True Chances of an Underdog Winning

To identify the true chances of an underdog winning varies in each sport, and I would say that the three important things to consider before placing a bet like this are the following:

  1. Look at the current odds and implied probability rate currently being offered for that team/individual/horse, etc. In other words, look for ‘underdogs’ with good odds/IPRs
  2. Recent form/historical results – if the underdog is currently in form (and its opponent is currently having a poor run of form), has won all of its recent fixtures, and generally does well against the opponent historically, then it might be worth betting on
  3. Don’t bet on the underdog too often, no matter how tempting it is, unless you have done enough research and firmly believe that the available statistics are pointing to the fact that the underdog has a good chance of winning this time.

Final Thoughts

To sum up, the underdog isn’t always a losing bet, but each sport is different in terms of how the bettor should perceive the underdogs. The important thing to remember is that the odds and implied probability rates are there for a reason.

With that said, placing a wager on the ‘odds-on’ favorite each time also doesn’t guarantee that you will win because, in sports betting, anything can happen. It’s about finding balance between betting on the favorites and the underdogs.

There are many variables that can affect the outcome, and you are always going to be subject to losses. Just remember to gamble responsibly when betting online, and perhaps consider using any safer gambling tools your operator provides.

I still believe that placing outsider/underdog bets is a risky way to make money, but the profit margins can be huge.

Also, don’t forget that there are ways you can mitigate risk to place more strategic bets that have a much greater chance of returning you a profit: researching, understanding the odds, and knowing the sport you are betting on.