Position size & risk
Fix your loss first; let the share count fall out of the math.
1R = the distance from entry to stop. Shares = dollars risked ÷ 1R. A tighter stop allows more shares; the dollar loss stays fixed.
Expectancy (in R)
Does the system make money over many trades?
Expectancy = (win% × avg win) − (loss% × avg loss), measured in R. Positive expectancy is the mathematical definition of an edge — an expectation, never a guarantee.
Pair these with the Risk & Position Sizing lesson and any strategy playbook.