Decision Journal, Not Predictions
How do you tell a good decision from a lucky one?
The idea
A journal records information, assumptions, probabilities, execution, and outcome so process can improve independently of luck.
In the real world
A sound trade can lose and a reckless trade can win.
Going deeper
Outcomes over short runs are dominated by variance, so judging decisions by results teaches the wrong lesson in both directions: reckless trades that win get reinforced, careful ones that lose get abandoned.
A journal separates the two by recording what you knew, what you assumed, what probability you assigned and how you executed — all before the outcome is known. Reviewed over dozens of decisions, it shows whether your probabilities are calibrated and where execution diverges from plan, neither of which is visible from a profit and loss statement.
Where it stops applying
Journals only pay off with enough entries and honest recording after losses, which is exactly when people stop writing. The discipline is in maintaining it through bad stretches.
Why it matters
Outcomes are noisy over short runs, so improving requires a record of the reasoning as well as the result.
Try this today
Review whether the process was followed before judging by profit or loss.
Test yourself
A trade taken on a whim returns 40%. A carefully planned one loses. Judging only by results, what do you learn?
Show the answer
The wrong lesson, twice. Recording the information you had, your assumptions, the probabilities you assigned and how you executed lets you separate a sound process from a fortunate outcome, which results alone can never do.
Learn this in the feed Answering from memory, then again days later, is what makes it stick.