In chapter 6 of The Theory of Poker, David Sklansky explains the idea of effective odds—how to correctly evaluate drawing decisions when there is more than one card and more than one betting round left to play.
Why Ordinary Pot Odds Aren’t Enough
When there’s only one card to come and one betting round left, decisions are simple:
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Compare your chance of improving to
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The pot odds you are currently being offered.
If the pot odds are better than the odds against hitting, you can justify a call.
However, when there are two or more cards to come, this simple comparison becomes misleading. Many players:
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Look at their chance of completing a hand with multiple cards to come,
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But compare it only to the current pot, ignoring the fact that they’ll likely have to call future bets as well.
This overestimates how good their situation really is.
Effective Odds: The Real Price of a Draw
Sklansky defines effective odds as the true ratio between:
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The total amount you stand to win if you make your hand, and
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The total amount you expect to lose if you miss, including all future calls.
Example idea:
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You flop a four-flush in hold’em with two cards to come.
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If you plan to go all the way to the river, you’re not just calling one bet now—you’re likely calling this bet and another one later.
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So your real cost might be, say, $30 total to win a final pot of $50, not $10 to win $30.
Once you include these future calls, the effective odds may be worse than the odds against hitting, making what looked like a good call actually a losing play—unless you expect to win more on later streets (extra calls from opponents when you hit).
A Backdoor Draw Example
With a backdoor (two-card) flush draw:
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Your chance of hitting is quite small (roughly 1 in 25 in the simplified example).
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The pot might appear to be laying a slightly better price than that on the flop.
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But in reality:
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Sometimes you’ll miss on the turn and fold, losing only the flop call.
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Sometimes you’ll hit a “halfway” card (e.g., one of the suit), call again on the turn, and then miss the river—now losing more than one bet.
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Only rarely will you hit both cards and win the whole pot.
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When you total up all the small losses and rare big win, the long-term result can be negative, even if the initial pot odds alone looked acceptable. Effective odds reveal the truth: the call is unprofitable.
When You Don’t Need to Use Effective Odds
There are a few important exceptions where you can ignore future betting:
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All-in situations
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If you or your opponent are all-in (or effectively so), there are no future bets to consider.
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You simply compare your chance of winning to the current pot odds.
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Likely “free card” situations
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If you have good reason to think your opponent will check on the next round a high percentage of the time (for example, with weak holdings or fear of your call), you may effectively get to see two cards for one bet, making the immediate pot odds more relevant.
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Calling for one card only in escalating limit structures
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In games where the bet size jumps sharply between streets (like $10 on one round and $50 on the next), it can be correct to:
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Call the small bet just to see the very next card,
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Then fold if you miss, rather than committing in advance to call the big future bet.
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In that case, you compare your chance of hitting only the next card to the current cheap price, ignoring later bets you do not intend to call if you miss.
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How to Calculate Effective Odds in Practice
The process is conceptually simple:
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Total your possible losses
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Add up every call you expect to make if you decide in advance to “go to the end” with your draw.
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Total your possible wins
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Start with the pot as it currently stands.
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Add the future money you reasonably expect to win from your opponents’ calls when you hit (but not your own future bets).
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Form the ratio
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Effective odds = Total possible win : Total possible loss.
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Compare this ratio to your actual chance of making a winner.
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If your chance of winning is better than what the effective odds demand, the draw is profitable.
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If not, it’s a fold—even if the immediate pot looks tempting.
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Main Takeaway
Chapter 6 teaches that:
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With more than one card to come, raw pot odds are often an illusion.
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You must look at effective odds, which account for future bets you’ll have to call if you continue.
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Only when future betting is capped, unlikely, or deliberately avoided (one-card-only calls) can you safely ignore effective odds and treat it like a simple one-card problem.
Understanding this distinction keeps you from overplaying draws and making long-run losing calls that feel right but quietly bleed your bankroll.