The following article was written by Eric “Performify” Foster on MMAjunkie.com for the premiere issue of FIGHT! Magazine.
Converting a Line to a Percentage
Converting allows us to establish the exact percentage chance a fighter is being given to win the fight. Converting is actually a very simple bit of math. However, it is a slightly different calculation for the favorite vs. the underdog.
For the Favorite: Amount to win $1 / (Amount to win $1 + $1) = Favorite %
Take BJ Penn (-500) vs. Jens Pulver (+400) for the Ultimate Fighter 5 finale. With Penn at -500 you would wager $500 to win $100, so $5 to win $1. Plugged in to the formula: $5 / ($5 + $1) is 5 / 6 = .83 or 83%.
For the Underdog: 1 / (Amount won when wagering $1 + $1) = Underdog %
For Pulver you win $400 wagering $100. Applying that same ratio, you win $4 wagering $1. Plugging that in to the underdog formula: 1 / $4 + $1 is 1 / 5 = .20 or 20%.
You will notice the two percentages add up to more than 100%. This gap in the moneyline is how the sportsbook makes its commission.
There are a number of free calculators that you can use to do the conversion for you – hop to Yahoo.com and search for “moneyline converter” for several alternatives.
Starting to Use a Percentage to Identify Value
Identifying value is ultimately a complex process and will be the subject of future articles. To get started, understand that being a winning sports bettor is ultimately about identifying and pushing small edges for a long-term profit.
To identify these edges, start by setting your own winning percentage for a fighter and compare it against the percentage from the moneyline conversion. By identifying and betting significant differences, we build value in the long run.
If we believe a fighter should have a 25% chance of winning (+300) and we find a line offering a 20% chance of winning (+400), we have identified an edge. It may not seem like a lot, but it is actually very significant Ã¢?? more than enough to bet.
With the line of +400 we could bet $100 to win $400. If the “true” odds of winning were 25% and you were offered this bet four times – say four fights on a card, all +400 underdogs, each with true odds of 25% – probability dictates you would lose three times and win once. You would profit $400 from the win but lose $300 from the three losses, for a net profit of $100. Expressed another way, you would have a positive expected value of $25 on the $100 wager.
You obviously won’t win every time you identify an edge, especially an edge in an underdog. In the example above, even with the large edge identified you still expect to lose that bet three times out of four. The idea of the “long run” means the one time out of four you do win will show a profit on the series.
A Real-World Example
For a real-world example let’s start with my UFC 71 predictions from MMAjunkie.com. Late replacement Houston Alexander came in as a big +450 underdog to Keith Jardine, just an 18% chance of winning.
I was able to identify clear value in the line for Alexander, writing “I do expect this fight will be more competitive than most expect.” I went on to recommend a bet on Alexander saying “I can recommend a play on Alexander as the underdog. This line should be closer than -600 for someone with HoustonÃ¢??s ability and experience.”
While there were many factors which went in to the pick, ultimately I assigned my own probability to Alexander winning the fight and comparing my percentage with the 18% chance he was being given by the line. I had the fight as much closer and as such felt that Alexander represented a good bet.
Few people had done their homework on Houston Alexander prior to UFC 71. A search online showed Alexander with a 6-1 professional MMA record spread across seven years with significant gaps between fights, leading many to question Alexander’s qualifications for the fight.
Before UFC 71, MMAjunkie.com posted an interview with Houston Alexander in which they revealed that Alexander had been fighting continuously for these seven years and had more than 200 total fights, most of them amateur matches not listed in his “professional” record. We found out Alexander was athletic and strong, a well-rounded striker with heavy hands. We also found out that Alexander had excellent trainers, including former world champion kickboxer Mick Doyle.
This combination of factors meant we had found a fighter who was being significantly underrated by the oddsmakers. In short, we knew what much of the rest of the world didn’t, and we were able to capitalize on the big underdog for a very nice payday.
Performify’s Profit Points
- Know as much as you can about both fighters. Study!
- Evaluate public perception. Who is overrated or underrated?
- Shop for the best available betting line.
- Trust your instincts. Your first reaction is usually right.
- Read discussion from winning handicappers and experts.