The Decision Journal Habit Separating Good Judgment From Lucky Guesses
A leader approves a pricing change. Revenue climbs the following quarter. The leader concludes the pricing change worked.
Maybe it did. Or maybe a competitor stumbled, a currency shift helped margins, or a single large customer happened to renew that same month. Without a record of what the leader actually expected to happen and why, there's no way to separate the decision from the noise around it. The outcome gets credited to judgment when it may have owed more to timing.
Decision researcher Annie Duke has a name for this pattern. She calls it "resulting," using the outcome as the sole measure of whether a decision was good. "Learning occurs when you make a decision and have feedback," Duke said in an interview about her book Thinking in Bets. The trouble is that feedback only teaches the right lesson when leaders know what they actually expected before they learned what happened.
This is the quiet problem at the center of most executive decision-making. Leaders rarely go back and test their own calls with any rigor. A good outcome and a lucky outcome end up feeling identical in hindsight, and the lesson that should have been learned never gets learned. The decision journal exists to close that gap.
Why Good Outcomes and Lucky Outcomes Feel The Same
Hindsight is a poor teacher because it edits the story after the fact. Once an outcome is known, the brain reconstructs the reasoning that led to it, smoothing over the doubts, the missing information, and the assumptions that turned out to be wrong. Psychologists call this hindsight bias, and it's one of the best-documented distortions in decision science. It makes every past call look more deliberate than it actually was.
A closely related problem compounds it. Francesca Gino, a behavioral scientist at Harvard Business School, has found that people judge a hiring decision by the new employee's performance rather than the fairness of the process, in her Harvard Business Review piece What We Miss When We Judge a Decision by the Outcome. Jonathan Baron and John Hershey demonstrated the same effect experimentally in 1988, in Outcome Bias in Decision Evaluation: identical decisions get rated as wiser or more foolish purely on how they turned out, even with identical information available to the evaluator.
Executives are especially exposed to this because so many of their decisions play out over months or years, with dozens of other variables moving at once. A reckless call that happens to land gets remembered as strategic brilliance. A well-reasoned call that runs into an unlucky break gets remembered as a mistake. Without a contemporaneous record, there's no way to tell which one actually did the work.
The cost isn't just intellectual honesty. It compounds. A leader who credits a lucky call to skill will lean on that same flawed process again, with worse odds next time. Peter Drucker called the fix feedback analysis in his Harvard Business Review essay Managing Oneself: write down what you expect a key decision to produce, then check the actual result against it months later. Writing down the reasoning before the outcome exists to distort it interrupts the cycle.
What A Decision Journal Actually Captures
The practice is simple enough to sound unremarkable, which is exactly why most leaders skip it. Before a consequential decision, write down five things:
The decision itself, stated plainly
What you expect to happen and by when
The key assumptions the expectation depends on
The conditions that would change your mind
Your confidence level, expressed as a number rather than a word
That last point is where most executives resist. "High," "medium," and "low" let everyone reinterpret the label once the result is in. A number does not.
That's the entire entry. No elaborate template, no committee review, 5 to 10 minutes at most. The value isn't in the writing. It's in what the entry allows later, when the outcome is known and the temptation to rewrite history sets in.
A decision journal is not a diary of feelings about a decision and it isn't a retrospective written after the fact. Both of those exercises are useful in their own right, but they don't solve the hindsight problem because they're written with the answer already in hand. The entry has to exist before the result does, or it can't do its job.
Building The Habit Before Q4 Pressure Hits
The fourth quarter compresses decision-making in a way no other period does. Budgets need to close, forecasts need to firm up, and staffing calls get made against a deadline instead of a preference. Under that kind of pressure, leaders default to whatever process is already a habit. If the habit isn't already routine by the time Q4 arrives, it won't get adopted mid-crunch, and the same untested pattern of judgment will run one more cycle unexamined.
Starting now, with 6 weeks of runway before the quarter's pace picks up, gives the habit time to become automatic rather than another item competing for attention during the busiest stretch of the year. A few entries a week is enough. The goal isn't volume. It's consistency on the decisions that carry weight, capital, personnel, strategic direction, not the routine calls that don't need this level of scrutiny.
Set a recurring 15-minute block, weekly is sufficient. Skip the trivial decisions. The practice loses value fast if it becomes an administrative burden rather than a discipline. A few operating norms keep it that way. Put the 6- and 12-month reviews on the calendar rather than leaving them to memory. Grade the process separately from the result, so a well-reasoned call that ran into bad luck isn't punished like a reckless one. And log the dissent that got voted down. A documented objection is often the clearest evidence of what the team actually knew.
What Changes When You Review The Entries
The real payoff arrives 3, 6, and 12 months later, when the entries can be checked against what actually happened. This is where the practice earns its place as a leadership tool rather than a personal productivity trick.
Three patterns tend to surface on review. First, decisions where confidence was high and the outcome matched, which is genuine judgment working as it should. Second, decisions where confidence was high but the outcome missed, which points to a flawed model of how the business or the market behaves, worth investigating directly. Third, and the one leaders find hardest to accept, decisions where confidence was low but the outcome landed well anyway. That third category is where luck lives, and pretending otherwise is how organizations end up repeating a favorable roll of the dice as though it were a strategy. Failure naturally invites this kind of scrutiny. Success usually closes the file instead, which is backward, since a lucky win reinforces confidence in a process that may not deserve it.
Reviewing entries as a set, rather than one at a time, reveals something an individual decision never will: a calibration pattern. A leader who is consistently overconfident will see high-confidence entries missing their mark more often than the stated percentage would predict. A leader who is underconfident will see the opposite. Neither pattern is visible without a written record to check against.
Daniel Kahneman and Gary Klein reached a related conclusion when they examined when professional intuition deserves trust. Confidence itself proves nothing, Kahneman argued: overconfidence comes from how coherent a story the mind can construct, not from how well that story is grounded in reality. "The second factor is whether decision makers have a chance to get feedback on their judgments," Klein added, in the McKinsey Quarterly interview Strategic Decisions When Can You Trust Your Gut. Without that loop, experience accumulates without turning into expertise.
The practice is useful beyond the individual leader, too. When an executive team keeps it collectively, patterns of judgment across the group become identifiable, not just individual blind spots but where the organization as a whole tends to misjudge risk, timing, or market response. That's a far more valuable signal heading into annual planning than a year-end retrospective assembled from memory.
The Discipline Worth Starting Now
None of this requires new software or a formal program. It requires a notebook or a shared document, and the discipline to write the entry before the outcome is known. The barrier isn't difficulty. It's that the habit has to survive contact with a leader's own certainty, and certainty is uncomfortable to write down when it might later prove wrong.
That discomfort is the point. The habit doesn't just separate good judgment from lucky guesses after the fact. It changes how a leader reasons through the decision in the first place, because the knowledge that the reasoning will be checked later tends to sharpen the reasoning offered now.
"Experience is the name every one gives to their mistakes," wrote Oscar Wilde in Lady Windermere's Fan. The line is 134 years old and still describes most executive postmortems. Experience only earns that name when someone bothered to write down what they believed before they found out whether they were right.
Q4 will bring decisions made fast and under pressure, the same as it does every year. The leaders who enter that stretch already keeping a record will have a genuine account to learn from once the quarter closes. The ones who don't will be left, once again, with a set of outcomes and no way to tell which ones they actually earned.
When ACG Becomes Valuable
Growth, leadership transitions, and performance pressure all expose decisions that comfort never tested. Aspirations Consulting Group helps executive teams bring the same rigor to their judgment that they already bring to their numbers, building the habits and governance that turn experience into expertise rather than repetition. Learn more about our advisory services.
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Thanks for reading!
~ Jerry Justice
Living to Serve, Serving to Lead™
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