Expected value
Expected value in trade review
Expected value asks whether the payoff is attractive after combining probability, average gain, average loss, and costs. A high success percentage alone does not prove the trade is good.
Hypothetical example
A trade risking $240 to make $760 with a 45% estimated probability has simplified EV of 0.45 × 760 - 0.55 × 240 = $210 before costs. If the probability estimate is unsupported, the score should be penalized even when the math looks positive.
Why low success percentage can still work
A low-probability setup can still have positive expected value if the wins are large enough relative to losses. The relationship matters more than the probability headline.
Primary reading: Investor.gov risk tolerance overview · FINRA options overview and risk · SEC Investor Bulletin on options · OIC options pricing overview · OCC Options Disclosure Document
