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The Decision Journal: A Simple Tool That Changes Everything
Keeping a record of your decisions — including what your gut said at the time — is the fastest way to build calibrated intuition. Here's exactly how to do it.
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Keeping a record of your decisions — including what your gut said at the time — is the fastest way to build calibrated intuition. Here's exactly how to do it.
Your gut feeling is sometimes genius and sometimes garbage. Here's a research-backed framework for knowing which is which — before you act on it.
Here's a riddle: you make thousands of decisions every year, each one a chance to get a little wiser, and yet most people's judgment at fifty isn't measurably sharper than it was at thirty. All that experience, and the needle barely moves. Why?
Because nobody closes the feedback loop. You make the call, life barrels forward, and by the time the outcome becomes clear, you've forgotten what you were actually thinking when you decided -- what your gut said, what the alternatives were, whether you felt confident or queasy. The result gets absorbed into a vague sense of "that worked out" or "that didn't," like a coin tossed into a wishing well. No retrieval. No learning. Just a fading ripple.
A decision journal fixes this. Think of it as a mirror with a time delay -- it shows you exactly who you were as a decision-maker at the moment you pulled the trigger, then invites you to compare that portrait with what actually happened. It's the single most effective tool for turning raw experience into calibrated judgment, and it takes less than five minutes per entry.
A decision journal is exactly what it sounds like: a written record of significant decisions, captured at the time you make them and reviewed after the outcomes become clear. Simple enough to describe on a napkin. Hard enough to maintain that almost nobody does it.
The concept has roots in several traditions. Annie Duke, the former professional poker player turned decision strategist, advocates for it extensively -- she'd argue it's the closest thing civilians have to a poker player's hand history. Shane Parrish of Farnam Street has written about it as a core tool for clear thinking. Ray Dalio's "Principles" framework includes systematic decision logging as a foundational practice. What unites all of them is a healthy suspicion of the stories we tell ourselves after the fact.
And that suspicion is well-earned. The core insight is deceptively simple: you cannot learn from decisions if you don't remember what you were actually thinking and feeling when you made them. The Decision Intelligence course integrates decision journaling as a core practice and provides frameworks for extracting maximum learning from each entry.
Here's the problem: memory is a terrible stenographer. After a decision works out, you remember being more confident than you were. ("I knew it all along.") After it fails, you remember having doubts you never actually expressed. ("I had a bad feeling about that.") This is hindsight bias, and it's not a minor nuisance -- it systematically prevents you from learning the truth about your own judgment. Your brain is rewriting the record in real time, and it's doing it in your favor.
A decision journal defeats hindsight bias by capturing the truth before your memory has a chance to edit it.
Every decision journal entry has three parts: the pre-decision capture, the decision itself, and the post-outcome review. Think of it like a scientific experiment -- you record the hypothesis before you run the test.
Write this down at the moment of decision, before you know the outcome:
The situation. What's happening? What decision am I facing? One or two sentences. No essays -- just enough to reconstruct the scene later.
The options. What are the realistic alternatives? List them briefly. If you can only see one option, that's worth noting too -- single-option framing is often a sign that something's been decided emotionally before the analysis began.
My gut feeling. What does my body/instinct say? Which option feels right? Note where you feel it -- chest, stomach, a sense of expansion or constriction. Be specific. "My gut says take the job" is okay. "My stomach feels heavy when I think about staying, and there's a lightness in my chest about leaving" is better. The body speaks in sensation, not sentences, and the more precisely you translate, the more useful the record becomes.
My analysis. What does the rational case say? What do the facts, data, and advice point toward?
My confidence. On a scale of 1-10, how confident am I in this decision? This number will feel almost silly to write down. Do it anyway -- it's critical for calibration later.
What I expect to happen. Write a specific prediction. Not "it'll probably work out" -- something concrete. "I expect this hire to perform above average in the first six months." "I think this investment will return 15-20% over two years." Vague predictions are unfalsifiable, and unfalsifiable predictions teach you nothing.
Record what you decided and the date. That's it. The shortest part of the journal is the decision itself -- which tells you something about where the real work lives.
When the outcome becomes clear, return to the entry. This is the part that feels like opening a time capsule -- and sometimes it's just as surprising.
What actually happened. State the outcome factually. Resist the urge to editorialize.
Was my gut right? Compare the gut feeling you recorded with the actual outcome. No editing, no rationalizing. The gut said X. The outcome was Y. Did they match? This comparison requires the kind of honesty that feels uncomfortable, which is exactly why it works.
Was my analysis right? Same comparison for the analytical case.
Was my confidence calibrated? If you said 8/10 confidence, did the decision work out roughly 80% of the time across similar entries? Over many decisions, this reveals whether you're overconfident, underconfident, or well-calibrated. (Spoiler: you're almost certainly overconfident. Welcome to the club.)
What did I miss? What information or signals were available that I did not weight correctly? This is the highest-value question in the entire journal -- the one that actually rewires your future pattern recognition. The pre-mortem technique is a powerful companion to the decision journal -- it helps surface the gut-level concerns that might otherwise remain unrecorded until after they've been proven right.
People who maintain a decision journal for three months or more consistently report several discoveries -- and they tend to arrive in a predictable order.
Your gut is better in some domains than others. This is the first and most useful revelation. You'll find that your intuitive signals are highly reliable in certain types of decisions -- maybe interpersonal judgments, or creative calls, or financial assessments -- and unreliable in others. This isn't a character flaw; it's a map. It tells you when to lean on your gut and when to demand more evidence. For a structured approach to combining these two channels, see The Hybrid Decision.
Your confidence is miscalibrated. Almost everyone discovers this, and almost everyone is humbled by it. Decisions rated 9/10 confidence work out maybe 60-70% of the time. That's a thirty-percent gap between how sure you feel and how sure you should feel. The silver lining: once you see the gap, you naturally start building in more margin for error. You learn to hold your certainty a little more loosely, the way a good scientist holds a hypothesis -- firmly enough to act, lightly enough to revise.
You repeat the same mistakes. Without a journal, each bad decision feels unique -- a special snowflake of misfortune. With a journal, patterns emerge with almost embarrassing clarity. You keep hiring people who interview well but underperform. You keep taking on projects that feel exciting at the start and draining by month two. You keep ignoring the same type of gut signal -- that faint "hmm" you wave away because the spreadsheet says yes. Seeing the pattern is the first step to breaking it, and breaking it is the first step to wondering why you tolerated it for so long.
Your judgment actually improves. This is the payoff -- the reason the whole exercise is worth the five minutes. By closing the feedback loop that normally stays open, you give your brain the data it needs to recalibrate. Over months, your gut feelings become more reliable, your confidence becomes better calibrated, and your blind spots become visible. You're not just making decisions anymore -- you're learning from them systematically. It's the difference between driving with your eyes open and driving with a dashboard.
Which decisions to journal. Not every decision merits an entry -- you'd lose your mind journaling lunch choices. Focus on decisions that are significant (meaningful consequences), uncertain (not obvious what to do), and reversible only at a cost. Career moves, hiring calls, major purchases, strategic pivots, relationship decisions, creative bets. If you find yourself lying awake thinking about it, it probably deserves an entry.
Format. Digital or paper, whatever you'll actually use. A simple note-taking app works fine. A dedicated notebook works fine. Fancy templates are unnecessary and often become an excuse to spend time on the container instead of the contents. The format matters far less than the habit.
Review cadence. Set a quarterly reminder to review past entries where outcomes are now clear. This review session is where the real learning happens -- it's the equivalent of watching game tape. Block 30 minutes, go through the entries, and look for patterns. Bring coffee. You'll want it.
Keep it honest. The journal is private. Nobody's grading you. Write what you actually feel, not what sounds reasonable. If your gut says "I don't trust this person and I don't know why," write that. If your analysis says "this is a bad idea but I want to do it anyway," write that. The more honest the input, the more valuable the output. Think of it this way: you can't calibrate a thermometer that lies about the temperature.
Individual decision journal entries are useful. But the real power is cumulative -- it compounds like interest, except the currency is self-knowledge.
After six months of entries and reviews, you have something most people never develop: an empirical map of your own judgment. Not a flattering story about your instincts, not a mythology of your greatest hits -- an actual map, complete with marked trails and clearly labeled dead ends. You know where your instincts are sharp and where they mislead you. You know whether you tend toward overconfidence or excessive caution. You know which types of gut signals to trust and which ones to interrogate further.
This is calibrated intuition -- not intuition that's always right, but intuition whose reliability you understand. And understanding the reliability of your own judgment turns out to be far more valuable than trying to be right every time. A compass that's off by five degrees is useful if you know about the five degrees. A compass you think is perfect will walk you into a swamp. If you want to accelerate this calibration process, particularly for moments when the pressure is on and the stakes are high, the Intuition Under Pressure course pairs journal-based reflection with real-time practices for reading your signals under stress.
The best decision-makers aren't the ones who never make mistakes. They're the ones who know, with increasing precision, when they're likely to be right and when they're likely to be wrong -- and adjust accordingly.
A decision journal is how you build that knowledge. Five minutes at a time. One honest entry after another. The kind of practice that feels almost too simple to matter, right up until the moment it changes everything.
