One of the most common review mistakes is judging a decision only by its outcome. This outcome bias can make a winning trade look correct even when it broke the plan, or make a valid losing trade look like a mistake.
Separate four types of trade
- Winner inside the plan.
- Winner outside the plan.
- Loser inside the plan.
- Loser outside the plan.
This classification forces process and outcome to be reviewed separately.
A poor decision can win
Entering without a setup, taking too much risk or moving a stop can still end in profit. If you reward only the outcome, that behaviour may be reinforced and repeated at a larger future cost.
A good decision can lose
A strategy with statistical edge includes normal losses. If a trade respected setup, risk and management, a negative result alone does not invalidate the decision.
What to measure
Alongside P&L, record plan adherence, main mistake, risk in R and any relevant deviation. Then compare expectancy and drawdown for disciplined trades versus rule-breaking trades.
Change the review question
Instead of starting with “did I win or lose?”, ask “did I do what was planned?”. Then interpret the outcome inside a sufficient sample.