What an Edge Actually Is

Ask most new traders what an edge is and they describe a win rate. "I win seven out of ten." It sounds like an edge. It is not, on its own.

A trader who wins 70 percent of the time but loses 4R on every loser and makes 1R on every winner is losing money. A trader who wins 35 percent of the time but makes 3R when right and loses 1R when wrong is making money. The win rate did not tell you which one survives.

An edge is positive net expectancy. It is the amount you expect to make, on average, per trade, once you account for both how often you win and how much you win and lose. Everything in this module builds on that one definition.

Expectancy = (Win% x Average Win) - (Loss% x Average Loss)

Read it plainly. Take how often you win, multiply by how much you make when you win. Take how often you lose, multiply by how much you lose when you lose. Subtract the second from the first. If the result is positive after costs, you have an edge. If it is negative, you do not, no matter how good the win rate looks.

Worked example. Win rate 40 percent, average win 300 dollars, average loss 150 dollars.

• Win side: 0.40 x 300 = 120
• Loss side: 0.60 x 150 = 90
• Expectancy: 120 - 90 = 30 dollars per trade

A 40 percent win rate is profitable here because the winners are twice the losers. Now flip it. Win rate 70 percent, average win 100 dollars, average loss 300 dollars.

• Win side: 0.70 x 100 = 70
• Loss side: 0.30 x 300 = 90
• Expectancy: 70 - 90 = negative 20 dollars per trade

Same trader, far higher win rate, and the account bleeds. This is why we never look at win rate alone.

The word net matters. Commissions, fees, and slippage come out of every trade before you ever see the expectancy. A setup that looks like it has a small positive edge on paper can be flat or negative once real execution costs are subtracted.

When you calculate your own expectancy later in this module, use your actual fills and your actual fees, not the prices you wished you got. An honest edge is measured net.