A trade teaches very little if the record says only “made $60.” The same result could come from a sound idea, excessive size, a lucky fill or ignoring an exit until the market recovered. A useful journal makes those explanations distinguishable.
The hard part is preserving what you believed before you knew the outcome. Once the result is visible, it becomes surprisingly easy to remember having expected it.
The decision before the fill
A short entry can answer four questions: what do I think the market is missing; what would change that view; over what period should it matter; and what position expresses it? Include the evidence available at the time, rather than a later article that makes the trade look obvious.
“Buying because it is strong” leaves too much room for reinterpretation. “The new guidance implies a larger margin improvement than the current price move reflects; I expect the next trading session to reassess that, and a clarification reversing the guidance would invalidate it” is something you can later evaluate.
Add the intended quantity, approximate entry, exit logic and anticipated costs. If the reasoning changes during the trade, create a new timestamped note. Editing the original into the explanation you prefer destroys the comparison.
The account record
Save fills, fees, funding and the final position, ideally from the transaction record. Screenshots help preserve the setup, but a cropped winning close can hide an earlier loss or an open position.
There is a research reason to use the records. Walters and Fernbach found that investors remembered performance too favorably through both distorted recall and selective forgetting. Looking up actual trades reduced overconfidence and intended trading in their experiment. That supports keeping an honest record; it does not establish that any particular journal template produces profits.
For comparison across trades, divide net PnL by the dollar loss planned at entry. If the initial planned risk was $40, a $60 net gain is +1.5R and a $50 loss is −1.25R. The latter shows that execution or the actual path exceeded the initial plan. Keep the original denominator, even if you later moved an exit.
Forecast, execution, and outcome
After closing, answer three different questions. Did the information develop as expected? Did you execute the intended trade? Did the trade make money after costs?
A forecast can be right while an entry arrives too late. An orderly, planned loss can occur when a sensible uncertain proposition fails. A rule-breaking trade can make money. Combining all three into a single “good trade” label makes it hard to know what to repeat.
If you repeatedly capture the expected move but lose after costs, execution or the size of the opportunity needs work. If fills are good but the expected reaction never arrives, better order placement will not repair the idea. Research such as Odean’s brokerage-account study is a useful reminder that additional trading can introduce both selection mistakes and transaction costs.
Comparing similar decisions
Group comparable trades by a category chosen before seeing their returns: the same event, setup or intended holding period. Then examine net results, loss size, missed opportunities and deviations from the plan. Include skipped setups if you want to learn whether your selection rule helps; a record containing only executed trades cannot answer that.
Small samples are clues. Three losses on a Friday do not establish that Fridays are untradable. Choose one proposed change, specify why it should help and observe it over the next comparable decisions. For example, repeated late entries point to a different change than timely entries followed by an event that never produces the expected response.