Positive Expectancy Systems

If you have a positive expectancy trading system, the only factors that determine how much money you will make per year are the number of trades the system generates, how much capital you allocate to the system, and how accurately you implement the trading signals. If you do not know whether your trading system is positive expectancy then why are you trading it? Expectancy is calculated using the profit or loss on each trade (net of trading implementation
costs) divided by the initial risk (using your stop loss) and then taking the average of this number of a series of trades. Systems that have positive expectancy will make money on average and those with negative expectancy will lose money.

Successful traders only trade systems where the odds of success are in their favor (i.e. the system is positive expectancy) so they know that making money is the result of accurately implementing the system and not just pure luck.