How Does Gambly Calculate a Bet’s Edge?

While Gambly doesn’t take a direct stance on games, we do calculate the edge–or expected ROI–for most (but not all) bets. Typically, the larger the market, the more likely we are to have the expected edge.

In simple terms, these calculations are a comparison of the current line on a bet at any given sportsbook and the consensus of market-making sportsbooks. 

We don’t take a viewpoint on games outside of market data, meaning this approach is top-down and sport-agnostic. For example, if DraftKings has the odds of a certain event at -110 and all other books are at -120, it’s likely that DraftKings’ line is off. But not all sportsbooks are created equally–some are sharper than others–and we use a weighted combination of each market-making book’s historical accuracy to calculate what the actual vig-free line should be, or the true odds. These formulas are sport-specific, meaning the “source of truth” for baseball is different than basketball, for example.

By comparing the current odds to a probable “true line” based on current market structure, it’s possible to calculate a bet’s expected ROI. If the vig-free true line based on market-making books is even money and FanDuel has that bet at +110, we can calculate the anticipated edge (even money is of course a coin flip, and getting paid +110 on each bet equates to a 5% edge).

There’s some nuance to how the “true line” is calculated–certain sportsbooks get different weights, adjustment for recent line movement, and so on–but in a nutshell, that’s how things work. A pure data-driven approach analyzing:

• current market structure (the odds across all sportsbooks in real-time)
• historical accuracy of each sportsbook for each sport
• derivatives: comparing -6.5 (-110) to -7 (+105) in NFL, for example

 

How can Gambly's derivatives help me?

Derivatives are betting markets that are related to the three main markets. This includes a wide range of potential bets, including things like first-half and first-quarter bets, alternative spreads and totals, and so on. Sportsbooks typically derive these numbers using historical models and the current numbers on the main markets.

Pricing these markets can be quite difficult…

Should you bet an NFL favorite at -1 (-115) against the spread or at -125 on the moneyline? How does the answer change if the total is 38.5 versus 51.5?

When looking at alt markets, how do you know which of the many different spreads and totals is mathematically the best option?

Gambly provides you with the expected ROI on all derivatives, letting you compare lines across different markets.

This process is also important for comparing spreads and totals, which are often different across sportsbooks. How often do you see the exact same spread or total across every sportsbook? It’s pretty rare. It’s absolutely pivotal to know if you should be betting over 46.5 (-110) or over 47 (+100).

Building these models to compare apples-to-oranges bets is extremely difficult but absolutely necessary to get the best odds. Gambly does the hard part for you.

 

What's so great about top-down betting?

There are a multitude of ways to make profitable bets, all of which ultimately come down to determining the “fair price” for a bet and uncovering situations when sportsbooks are most off from that number.

Top-down betting is the optimal path for almost all bettors, though, because it allows one to leverage the cumulative knowledge of other smart bettors. When Pinnacle–a sharp sportsbook that takes action from the best gamblers–moves a line to -115 and FanDuel is still at even money, it signals that Pinnacle has information (likely from a sharp bettor) that signals even money at FanDuel is probably now a good bet.

The benefits of top-down betting include:

• Timeless–no need to continually update a model and worry if it’s still beating the market
• Ability to leverage the work of sharp bettors
• Far larger pool of available bets (albeit at a smaller edge)
• More bets, less bankroll variance 
• A higher degree of confidence in being on the right side
• Can be used in combination with a bottom-up handicapping approach

The reality is that almost all bettors are better off starting with a top-down approach and then searching for the bets which are most intriguing to them based on personal factors, which is exactly what Gambly is built to help you do.

You can read more about why you should be top-down betting.

 

In a Nutshell

Gambly's edge calculations are among the most accurate you can find because of our commitment to data science and integrity.

We use real-time data.

We continually refine our process to improve our calculations.

We form accurate "true lines" based on many sport-specific data points.

We can accurately compare apples-to-oranges bets in a way that others cannot do–such as knowing when to bet -7 vs. -6.5 or over 38.5 instead of over 38–because of our commitment to accurate data science.

In a nutshell, we take a lot of pride in our edge calculations; the aim is to remove all of the complex and challenging work behind the scenes so you can make profitable bets as efficiently as possible.