Strategies · Lesson 2 · Beginner

Think in edge, the series counts

You understand why an edge is only a probability over many trades and why you have to take every valid trade.

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The advantage is thin

Richard Dennis says an edge only needs to be just above 50 percent, 53 percent is enough. The rest is discipline and sizing.

Douglas's five truths: anything can happen, you do not need to know what comes next, wins and losses are randomly distributed, an edge is only a higher probability, every moment is unique.

Flip the coin often enough and the edge separates from chance.

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Over 10 trades a 53 percent edge looks like pure chance. Only over hundreds of trades does it become visible. Kahneman calls the error of judging from small samples the Law of Small Numbers.

Test yourself

You have four losers in a row with your tested setup. What do you do?

Keep trading the setup unchanged, four trades say nothing
Switch approach immediately
Increase leverage to make up the losses

The key points at a glance

An edge is only a higher probability, not a certain outcome.
Wins and losses are randomly distributed, the advantage shows up only over the series.
You judge an edge well above 100 trades, not after 10.
Take every valid trade, do not switch approach after two losers.

Deep dive

How long is a normal losing streak?

Losing streaks feel like a broken approach but are pure statistics. At a 50 percent win rate, four losers in a row is 0.5 to the power of 4, so roughly 6 percent. Over 100 trades a streak like that shows up several times.

Five or six losers in a row are normal over a long series
Size down during a losing streak, do not do catch-up sizing
Elder's 6 percent rule: stop trading when the account drops 6 percent below last month
At 2 percent risk per trade that is three losers, then take a break

Expectancy: the formula behind your edge

An edge is an expected value, not a win rate. Expectancy equals (win rate times average win) minus (loss rate times average loss). 40 percent winners at a reward-to-risk of 1 to 2.5 is clearly positive, 70 percent with tiny targets can lose money.

Taleb's convexity: with a capped loss and open-ended profit you can be right less than half the time and still win. A few large winners more than make up for many small losers.

How many trades does an edge need to become visible?

Over 10 trades a real 53 percent edge looks like chance, and chance looks like an edge. Kahneman calls judging from mini samples the law of small numbers. It only becomes reliable over a three-digit number of trades.

The condition is consistency: the same setup by the same rules
20 of 23 Turtles made roughly 100 percent per year with teachable rules
The scarce thing was not the knowledge but the discipline
Run one setup mechanically 50 to 100 times on the demo exchange

Sources: Douglas, Schwager, Kahneman, Taleb

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