Most odds calculators use a simplistic Equal Margin method to remove vigorish from betting lines. However, true probability calculation is more complex, particularly when dealing with heavily lopsided odds. Drawing from academic research on soccer betting markets, we've developed a more sophisticated approach that recognizes how different calculation methods perform better in different scenarios.
Why a Blended Approach Works Better
When two teams are evenly matched, the Equal Margin method provides reliable results by distributing the vig proportionally. However, as odds become more lopsided, this method starts to break down. The Margin Proportional to Odds (MPTO) method excels with longer odds but can be less optimal when teams are closely matched.
Our dynamic blended approach takes advantage of both methods' strengths. For matchups with similar odds, we give nearly equal weight to both calculations. As the odds disparity grows, we progressively shift toward MPTO, ensuring more accurate probability estimates across all betting scenarios.
This adaptive methodology provides sharper bettors with a more precise tool for identifying true market probabilities, regardless of whether they're evaluating even matchups or games with heavy favorites.
Comparing No-Vig Methods Across Different Odds
Let's examine how each method performs across a range of odds scenarios. The table below compares the Equal Margin (EM), Margin Proportional to Odds (MPTO), and our Blended approach for various odds combinations. Pay special attention to how the differences between methods become more pronounced as the odds get longer.
| Original Odds | Equal Margin | MPTO | Blended | ||||
|---|---|---|---|---|---|---|---|
| Underdog | Favorite | Underdog | Favorite | Underdog | Favorite | Underdog | Favorite |
| -110 | -110 | -100.0 | -100.0 | -100.0 | -100.0 | -100.0 | -100.0 |
| +120 | -140 | +128.3 | -128.3 | +129.6 | -129.6 | +129.0 | -129.0 |
| +200 | -300 | +225.0 | -225.0 | +242.9 | -242.9 | +237.2 | -237.2 |
| +290 | -410 | +313.5 | -313.5 | +342.0 | -342.0 | +334.8 | -334.8 |
| +610 | -973 | +643.8 | -643.8 | +754.5 | -754.5 | +737.8 | -737.8 |
| +500 | -1000 | +545.5 | -545.5 | +676.5 | -676.5 | +652.8 | -652.8 |
| +860 | -1600 | +903.5 | -903.5 | +1127.1 | -1127.1 | +1100.4 | -1100.4 |
| +900 | -2000 | +952.4 | -952.4 | +1254.8 | -1254.8 | +1218.8 | -1218.8 |
| +1200 | -3000 | +1258.1 | -1258.1 | +1731.8 | -1731.8 | +1685.9 | -1685.9 |
| +2000 | -4000 | +2048.8 | -2048.8 | +2677.4 | -2677.4 | +2640.1 | -2640.1 |
| +20000 | -60000 | +20066.6 | -20066.6 | +30024.9 | -30024.9 | +29951.4 | -29951.4 |
| +50000 | -300000 | +50083.3 | -50083.3 | +85765.3 | -85765.3 | +85643.8 | -85643.8 |
Understanding the Results
Notice how the three methods produce nearly identical results for evenly matched contests (like the -110/-110 line). However, as the odds disparity grows, the differences become substantial. For extreme odds, like +50000/-300000, the Equal Margin method suggests a no-vig underdog price of +50083, while MPTO calculates +85765 - a dramatic difference that highlights why using the right method matters.
The decision to blend rather than rely solely on MPTO stems from real-world betting patterns. Sportsbooks typically receive heavier action on favorites, leading them to shade these lines differently than pure mathematics would suggest. The Equal Margin method often better reflects these market dynamics, particularly in popular betting markets where public money drives line movement. This is especially true in major sports where recreational bettors consistently back favorites.
Our Blended approach provides a balanced solution, staying close to Equal Margin results for typical odds ranges while shifting toward MPTO's more realistic adjustments for extreme odds. This methodology acknowledges both the mathematical principles of odds calculation and the practical realities of how sportsbooks manage their risk exposure.
Conclusion
The betting market's complexity demands more nuanced solutions than one-size-fits-all approaches to removing vigorish. Our new Blended methodology in Nostradamus No-Vig combines the market-aware aspects of Equal Margin with the mathematical precision of MPTO, delivering more accurate probability estimates across all odds ranges. This enhancement represents our ongoing commitment to providing bettors with the most precise tools for identifying true market value.
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