Why Taking the Best Odds Matters, Part II: What If You Sized Your Bets Correctly?
The Setup
In Part 1, we ran a simulation of 1000 bets comparing two scenarios:
Best Book Odds: Taking the best available line and sizing with Kelly
“Your Odds”: Taking suboptimal odds but using the same Kelly sizing as Best Book (simulating that you were tailing someone at their same recommended units, even though you got a worse price)
The results were brutal. Best Book finished at +21.78 units. Your Odds finished at -25.93 units. A 47.71 unit swing - same opportunities, just worse execution.
But here's the question that came up: What if you properly adjusted your bet sizing for the odds you were actually getting?
The Fix: Recalculate Kelly for YOUR Odds
The problem in Part 1 wasn't just taking worse odds - it was using the wrong bet sizing for those odds.
When the Value Finder shows 0.5u at +360, that sizing is calculated for +360. If you take +320 instead, the correct move is to recalculate Kelly for +320.
Here's what that means in practice:
If the recalculated Kelly is still positive → bet that amount (smaller than the original recommendation)
If the recalculated Kelly is zero or negative → don't bet at all
The Part 2 Simulation
I ran the same 1000 bets, same outcomes, but added a third scenario:
Best Book Odds - Full Kelly at best available odds (same as Part 1)
Your Odds (Wrong Sizing) - Using Best Book Kelly at worse odds (Part 1)
Your Odds (Proper Kelly) - Recalculating Kelly for the actual odds taken
The Results
Best Book Odds
Final Profit: +21.78 units
Bets Taken: 1000
ROI: 5.2%
Your Odds (Wrong Sizing)
Final Profit: -25.93 units
Bets Taken: 1000
ROI: -6.2%
Your Odds (Proper Kelly)
Final Profit: +5.04 units
Bets Taken: 254 (25.4%)
Bets Skipped: 746 (74.6%)
ROI: 15.8%
The Transformation
Look at what happened:
Wrong sizing: -25.93u (LOSING)
Proper sizing: +5.04u (WINNING!)
That's a 30.97 unit improvement - just from sizing your bets correctly!
Why This Works
Remember from Part 1: 74.6% of the bets went from +EV to -EV when you took suboptimal odds.
With proper Kelly sizing, those 746 -EV bets become 0 unit bets. You don't take them. Kelly is telling you: "At these odds, this bet has no edge. Pass."
The remaining 254 bets are still +EV at Your Odds - just with a smaller edge. Proper Kelly sizes them down appropriately.
The result? You:
Skip 746 losing bets entirely
Size the remaining 254 bets correctly for their actual edge
Turn a -25.93u disaster into a +5.04u profit
The Trade-Off
There's a catch. Look at the total action:
Best Book: 419.57 units risked
Your Odds (Proper Kelly): 31.95 units risked
By only taking the 254 remaining +EV bets at proper sizing, you're betting 92% less money.
This is a cost of not having access to best odds. It's not just that you make less per bet - you have far fewer bets worth taking.
What This Means for You
If you can access the best book:
Take all the opportunities at full recommended sizing. You're maximizing your edge and your action.
If you can only get worse odds:
Recalculate Kelly for your actual odds
Skip bets where the new Kelly is zero or negative
Size down the remaining bets appropriately
Accept that you'll have less action overall
The honest truth:
Proper Kelly with worse odds (+5.04u) is still WAY better than wrong Kelly with worse odds (-25.93u). But it's not as good as Best Book (+21.78u).
The math is unforgiving. Worse odds = smaller edge = fewer bets worth taking = less profit.
The Bottom Line
Can you salvage a bad situation with proper sizing?
Yes. Absolutely. Going from -25.93u to +5.04u is a massive improvement. Proper Kelly sizing turned a losing bettor into a winning one.
But you're still leaving money on the table.
Best Book: +21.78u
Your Odds (Proper): +5.04u
Difference: 16.74u
That 16.74 units? That's the cost of not having access to the best lines - even when you do everything else right.
The Takeaway
Best case: Take best odds at full sizing → +21.78u
Salvageable: Take worse odds but size properly → +5.04u
Worst case: Take worse odds with wrong sizing → -25.93u
If you can't get the best odds, at least get your sizing right. But the real play? Get accounts at the books with the best lines.
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*This is Part 2 of our odds education series. I recommend reading Part 1 to understand why taking suboptimal odds costs you money.*
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