Boosted odds
Understanding Boosted Odds
Before applying this to betting, it helps to understand what a price actually tells you, and why the price on offer isn't always a fair reflection of the real chance of something happening.
What a price really means
Any price you're offered can be turned into a percentage chance. A price that pays double your stake back (ie. $2 odds) is implying a 50% chance of happening. A price that pays four times your stake is implying a 25% chance. The higher the price, the lower the implied chance, and vice versa.
This works in reverse too. If you already know the true chance of something happening, you can work out what a fair price for it would look like. A true 33% chance should be offered at a price that pays three times your stake, since 1 divided by 33% equals 3.
Why the offered price and the fair price don't always match
Whoever is offering the price builds in a buffer (the bookies margin, or vig) for themselves. This means the price you're offered is never really the exact fair price. Most times it's worse than fair, sometimes however, when it's boosted, it can be better than fair. This is when its becomes a positive expected value boost. (EV+)
Imagine a simple guessing game where you're paid out based on picking a number between 1 and 10. The fair price for guessing correctly should reflect a 1 in 10 chance. If the price on offer pays out as though your odds were closer to 1 in 5, you're being paid less than the fair value. If the price on offer pays out as though your odds were closer to 1 in 20, you're being paid more than the fair value, and that's a good deal.
The two things you always need
To work out whether a boosted price is actually good value, you need two things:
- The price being offered
- Your best estimate of the true, fair price for that same outcome
Once you have both, comparing them tells you whether the offer favours you or not. Getting an accurate fair price is the harder part, since it usually means looking past the offered price itself to work out what's really likely to happen. We suggest using the betfair lay odds where available, accounting for the usual indicators such as liquidity and time to event for accuracy. Other methods for true odds calculation can be found in the lesson here for using our True Odds calculator.