The Math of Ruin
Probability, expectancy, and why even winning strategies destroy accounts without proper sizing.
Most traders focus on winning percentage. Professional traders focus on expectancy. This module breaks down the mathematics of trading edge, explains why a 60% win rate strategy can still blow an account, and shows you how to calculate whether your strategy actually has positive expectancy.
Lessons
Win Rate vs Expectancy: What Actually Drives Profit
A trader can win 70% of trades and still lose money. Understanding expectancy is the core insight that separates professional traders from amateurs.
Drawdown: The Math Behind Surviving Losing Streaks
Every strategy has losing streaks. The question is not whether you will have them — it is whether your position sizing allows you to survive them.
The Gambler's Fallacy and Why It Destroys Traders
After 5 losses in a row, the next trade is "due" to win. This belief — the gambler's fallacy — is one of the most dangerous cognitive errors in trading.
Monte Carlo Simulation for Strategy Testing
Backtesting tells you what happened in one historical sequence. Monte Carlo shows you what could happen across thousands of possible sequences — including the worst case.
Building Your Personal Risk Budget
Risk budgeting is the discipline of allocating your total risk capacity across positions and time — so no single loss, day, or drawdown can permanently damage your account.