What Is a Decision Journal? The Simple Practice That Improves Every Choice You Make

What Is a Decision Journal?

A decision journal is a written record of the decisions you make, why you made them, and what you expected to happen. It's one of the most powerful journaling exercises for behavior change—a simple practice that turns your choices into learning opportunities instead of forgotten moments.

Later, you return to compare your predictions against reality. That's where the magic happens.

No complex system. No expensive app. Just a practice that forces you to confront the gap between what you thought would happen and what actually did.

Most people never do this. They make decisions, forget their reasoning, and then retrofit explanations after the fact. "I knew it all along," they say—even when they didn't. This is called hindsight bias, and it's the enemy of better judgment.

A decision journal is the antidote. It creates an honest record that your future self can't argue with.

"The only way to improve your decision-making is to study your decisions. But you can't study something you haven't recorded." — Shane Parrish

Why Decision Journals Work

The human brain is a storytelling machine. After something happens, it instantly creates a narrative that makes the outcome seem inevitable. You forget your uncertainty. You forget your alternative options. You forget how close you came to choosing differently.

This is adaptive for survival but terrible for learning. If you can't accurately remember your past reasoning, you can't improve your future reasoning.

The Psychology Behind the Practice

Decision journals work because they exploit several well-documented psychological principles:

• Commitment and consistency: Writing down your reasoning creates psychological commitment. You take your own thinking more seriously when it's on paper. Research by Robert Cialdini shows that written commitments are significantly more binding than mental ones—your brain treats them as promises to yourself.
• Metacognition: The act of explaining your decision forces you to think about your thinking. This catches errors before they become expensive. When you have to articulate why you're choosing Option A over Option B, you often discover gaps in your logic you hadn't noticed.
• Feedback loops: Comparing predictions to outcomes creates a closed loop that accelerates learning. Without this, you're just accumulating experiences without extracting lessons. Most people have 20 years of experience making decisions—but without a feedback loop, it's really one year of experience repeated 20 times.
• Accountability: Your journal becomes an honest witness that can't be gaslit by your future self's revisionist history. You can't claim you "always knew" something would fail when you have written evidence that you expected it to succeed.
• Reduced emotional interference: Writing creates psychological distance. Instead of being caught up in the emotion of a decision, you become an observer of your own thinking process. This distance improves judgment.

What the Research Shows

Studies on "pre-mortems"—imagining a decision has failed before making it—show they improve decision quality by 30%. Decision journals build on this by adding post-mortems: structured reflection after you know the outcome.

Research on deliberate practice confirms that improvement requires accurate feedback. Athletes watch game tape. Musicians record themselves. Chess players study their past games move by move. Decision-makers who want to improve need an equivalent record.

A study published in the Journal of Consumer Research found that people who wrote down their predictions were 40% better at estimating probabilities accurately over time. The act of making predictions explicit—and being forced to confront when they're wrong—calibrates your internal sense of certainty.

Philip Tetlock's research on "superforecasters" (people who are exceptionally good at predicting future events) found that they share one key habit: they keep track of their predictions and actively learn from their mistakes. A decision journal is simply applying this same principle to your personal and professional choices.

Who Should Keep a Decision Journal?

Decision journals are used by CEOs, investors, military strategists, and poker players—anyone whose outcomes depend on the quality of their judgment.

But you don't need to be managing billions or commanding armies. A decision journal helps anyone who:

• Keeps making the same mistakes — If you notice patterns repeating across relationships, jobs, or situations, a decision journal helps you see why. The problem isn't that you make bad decisions—it's that you can't remember the reasoning that led to them, so you repeat the same flawed logic.
• Struggles with big decisions — Career changes, relationship choices, major purchases—anything where you feel paralyzed by options. A decision journal forces clarity by making you articulate exactly what you're choosing and why.
• Wants to trust their intuition more — But only after calibrating that intuition against reality. Your gut feelings are only useful if they're accurate. A decision journal reveals whether your instincts are actually worth following.
• Is tired of regret — Not because you'll make perfect decisions, but because you'll understand why you made the ones you did. Regret often comes from not understanding our past selves. A decision journal preserves that understanding.
• Leads others — Parents, managers, coaches—anyone whose decisions affect people who trust them. When you're responsible for others, the stakes of good judgment multiply.
• Is building a business or career — Entrepreneurs and professionals make dozens of consequential decisions every week. The cumulative effect of slightly better judgment compounds dramatically over time.

If you're reading this, you probably fall into at least one of these categories.

The History of Decision Journaling

The practice of recording decisions isn't new. Benjamin Franklin famously created pro/con lists for difficult choices. But the modern decision journal—focused on predictions, reasoning, and review—emerged from several fields simultaneously.

In investing, figures like George Soros and Ray Dalio developed systematic approaches to recording investment theses and comparing them against outcomes. Dalio's "principles" approach at Bridgewater Associates essentially institutionalized decision journaling at the organizational level.

In poker, professional players began keeping detailed records not just of hands played, but of their reasoning at each decision point. They discovered that reviewing these records revealed thinking errors invisible in the moment.

Shane Parrish, through Farnam Street, popularized the decision journal for a broader audience. His template—emphasizing the mental and emotional state at the time of decision—added crucial dimensions that pure logic-focused approaches missed.

Today, decision journaling has spread to product managers, executives, doctors, and anyone else who recognizes that their success depends on the quality of their judgment.

The Core Components of Every Decision Journal Entry

An effective decision journal entry captures five essential elements:

1. The Decision Itself

State clearly what you're deciding. This sounds obvious, but many people are vague about their actual commitments. "I'm going to exercise more" isn't a decision. "I'm committing to the gym 3x/week for the next 6 months" is.

Be specific about what you're choosing and what you're choosing against. A decision only has meaning in contrast to its alternatives.

2. Your Reasoning

Why are you making this choice over the alternatives? What information are you basing it on? What assumptions are you making? This is the most important part—it's what your future self will evaluate.

Don't just list reasons. Explain the weight you're giving each factor. "The salary is higher" matters less than "I'm prioritizing salary over work-life balance because I have specific financial goals to hit in the next two years."

3. Your Expected Outcome

What do you think will happen? Be specific. Include probabilities if you can. ("I'm 70% confident this will work.") This creates a clear benchmark for later comparison.

The key is making predictions that are falsifiable. "This will probably be good" can never be proven wrong. "I expect to see a 20% increase in sales within 6 months" can be definitively evaluated.

4. Your Mental State

How are you feeling right now? Rushed? Confident? Anxious? Your emotional state affects your judgment more than you think. Recording it helps you spot patterns—maybe you make worse decisions when stressed, or better decisions when slightly uncertain.

Also note external factors: Did you sleep well? Are you hungry? Under time pressure? These seemingly small factors can significantly bias your thinking.

5. What Could Change Your Mind

This is often overlooked but incredibly valuable. Before committing to a decision, articulate what evidence would make you reconsider. This prevents you from becoming too attached to your choice and helps you stay open to new information.

How to Start Your Decision Journal

Starting a decision journal is simple. Maintaining it is where most people fail. Here's how to set yourself up for success:

Step 1: Choose Your Medium

Paper works. So does a notes app. So does a dedicated journaling tool. The best choice is whatever you'll actually use consistently. Some people prefer physical notebooks because the friction of writing slows their thinking. Others prefer digital because it's searchable.

Tools like Life Note can be helpful because they prompt reflection and help you spot patterns across entries over time. The AI-powered insights can surface connections between decisions that you might miss on your own.

Step 2: Set Your Threshold

You don't need to journal every decision. Start with decisions that meet at least one of these criteria:

• High stakes (significant money, relationships, or time)
• Irreversible (hard or impossible to undo)
• Uncertain (you genuinely don't know what will happen)
• Repeated (a type of decision you make regularly)

For most people, this means 2-5 decisions per week at first. As the habit becomes automatic, you might expand to include smaller decisions in specific domains where you want to improve.

Step 3: Create Your Template

Use a consistent format so you capture the same information each time. A basic template:

• Date:
• Decision: What I'm deciding
• Alternatives considered: What else I could do
• Reasoning: Why I'm choosing this option
• Expected outcome: What I think will happen (with probability)
• Mental/emotional state: How I'm feeling
• What would change my mind: Evidence that would make me reconsider
• Review date: When I'll check back on this

For a more comprehensive template with tracking features, see our Decision Journal Template.

Step 4: Schedule Your Reviews

The journal is useless without review. Set calendar reminders to revisit decisions after enough time has passed to see results. For most decisions, 3-6 months is sufficient. For major life decisions, annual reviews work better.

Consider doing a monthly "decision review" where you look back at all entries from 3-6 months ago. This creates a regular rhythm of learning.

Step 5: Start Small

Begin with one decision this week. Just one. Build the habit before trying to capture everything. Consistency beats comprehensiveness.

Many people fail because they try to journal every decision immediately. This leads to burnout and abandonment. Start with the minimum viable practice and expand only when it feels effortless.

How to Review Your Decision Journal

Recording decisions is only half the practice. The other half is returning to them with honest eyes.

Questions for Each Review

1. What actually happened? Just the facts. No interpretation yet. Write down the outcome as objectively as possible before analyzing it.
2. How does this compare to my prediction? Was I right? Wrong? Partially right? Be honest—your ego will want to claim credit for lucky outcomes.
3. Was my reasoning sound? Even if the outcome was bad, the reasoning might have been good. And vice versa—good outcomes sometimes come from bad reasoning (luck). This is the hardest distinction to make, but the most important.
4. What did I miss? Information, perspectives, alternatives I didn't consider. Were there warning signs I ignored? Experts I should have consulted?
5. What would I do differently? With the benefit of hindsight—but also: what could I realistically have known at the time? Don't beat yourself up for not having information that wasn't available.
6. What does this teach me about my decision-making? Look for patterns. Do you consistently overestimate your knowledge? Underestimate implementation difficulty? Ignore emotional factors?

The Outcome Trap

Here's something counterintuitive: don't judge decisions purely by outcomes.

A decision can be good even if the outcome was bad. You can make the right bet and still lose. You can fold a winning hand based on correct probability assessment. Poker players understand this intuitively—they don't judge a hand by whether they won, but by whether they played it correctly given the information available.

Similarly, a bad decision can have a good outcome. You can drive drunk and get home safely. That doesn't make drunk driving a good decision. You got lucky.

The question isn't just "Did this work?" It's "Given what I knew at the time, was this the right choice?" Focus on improving your process, not just your results. Over time, a good process produces better results than chasing outcomes directly.

Common Decision Journal Mistakes

1. Journaling After the Outcome

If you write your reasoning after you know what happened, hindsight bias has already corrupted the record. Always capture your thinking before you know the results. This is non-negotiable—a post-hoc journal is worse than no journal because it gives you false confidence in your reasoning.

2. Being Too Vague

"I think this will work out" isn't useful. "I'm 75% confident this will increase revenue by 20% within 6 months" gives you something to actually evaluate. Specificity is what enables learning. Vague predictions can never be proven wrong.

3. Only Journaling Big Decisions

The big decisions are obvious to track. But you can learn a lot from smaller, repeated decisions—hiring, spending, how you spend your time. These aggregate into your life's trajectory. A CEO who makes slightly better small decisions every day will outperform one who only focuses on the quarterly strategy.

4. Never Reviewing

A decision journal without reviews is just a diary. The learning happens in the comparison. If you're not going back, you're not growing. Many people enjoy the writing part but skip the uncomfortable review part. Don't be one of them.

5. Being Too Hard on Yourself

The goal isn't to feel bad about past decisions. It's to calibrate your judgment for future ones. Self-criticism without learning is just punishment. Approach reviews with curiosity, not judgment.

6. Stopping After a Few Entries

The benefits compound over time. Your first few entries teach you little. But after 50? 100? You'll start seeing patterns that transform how you think. The decision journal is a long game. The people who benefit most are those who maintain the practice for years.

7. Not Capturing Emotions

Many people focus only on logic and reasoning. But emotions drive decisions more than we admit. If you don't record how you felt, you miss a major source of insight. Anger, fear, excitement, boredom—all of these bias your judgment in predictable ways.

Signs Your Decision-Making Is Improving

After months of consistent journaling, you should notice:

• Better calibration: Your confidence levels match your accuracy. When you say 80%, you're right about 80% of the time. This calibration is rare and valuable—most people are consistently overconfident.
• Faster decisions: You spend less time spinning because you trust your process more. Paradoxically, slowing down to journal individual decisions speeds up your overall decision-making by building confidence.
• Less regret: Not because you make perfect choices, but because you understand why you made the ones you did. Regret often comes from feeling like we acted randomly or without thought. A decision journal proves otherwise.
• Pattern recognition: You catch yourself about to repeat old mistakes before you make them. "Wait, this feels exactly like the last three times I made this mistake..." becomes a common thought.
• Reduced outcome anxiety: You care more about making good decisions than about results you can't control. This is both psychologically healthier and practically more effective.
• Clearer thinking: The habit of articulating your reasoning improves your reasoning itself. Writing forces clarity that pure thinking often lacks.
• Better questions: You start asking yourself the right questions before deciding, not just after. The review framework becomes internalized.

Decision Journal Examples

Career Decision Example

Date: March 15, 2025

Decision: Accept the job offer from Company B instead of staying at Company A

Alternatives: Stay at current job (comfortable, known path), negotiate raise at current job, freelance

Reasoning: Company B offers 40% more money, a more senior title, and exposure to an industry I want to learn. The team seemed strong in interviews. Risk: new company, less job security, unknown culture. I'm weighting growth opportunity over stability because I'm early in my career and can afford to take risks.

Expected outcome: 70% confident this accelerates my career. 60% confident I'll enjoy the work. 80% confident I'll learn a lot regardless of outcome.

Mental state: Excited but anxious. Slept poorly last night. Might be slightly over-optimistic because I'm bored in current role.

What would change my mind: If I learned the company was in financial trouble, or if multiple people warned me about the manager.

Review date: September 2025

Financial Decision Example

Date: March 20, 2025

Decision: Invest $10K in index funds instead of paying down mortgage faster

Alternatives: Extra mortgage payment, high-yield savings, individual stocks

Reasoning: Mortgage interest rate (3.5%) is lower than expected market returns (7-10% historical). Tax advantages favor investment. Liquidity value—I can access the money if needed. I'm 15+ years from retirement, so time horizon supports equity exposure.

Expected outcome: 65% confident this outperforms extra mortgage payments over 10-year period. 90% confident it's the mathematically correct choice given current rates.

Mental state: Calm, analytical. Not feeling pressured. Made this decision after a week of research.

What would change my mind: If interest rates rose significantly, or if my job security became uncertain.

Review date: March 2027

Relationship Decision Example

Date: March 25, 2025

Decision: Have a difficult conversation with my partner about household responsibilities instead of continuing to feel resentful

Alternatives: Keep absorbing the extra work, passive-aggressively drop hints, leave the relationship

Reasoning: The resentment is building and affecting how I treat them. Direct communication has worked for us in the past. The short-term discomfort of the conversation is less than the long-term cost of growing resentment.

Expected outcome: 60% confident we'll find a workable solution. 30% chance it leads to a fight before resolution. 10% chance they react very badly and it creates bigger issues.

Mental state: Nervous but determined. I've been putting this off for weeks. Feeling slightly guilty for letting it get this far.

What would change my mind: If they were going through a crisis right now, I'd wait for a better time.

Review date: April 2025

Decision Journaling vs. Regular Journaling

Regular journaling is about processing experiences and emotions. Decision journaling is about improving judgment. Both practices are valuable, but they serve different purposes.

Many people do both—regular journaling for self-reflection and emotional health, decision journaling for clearer thinking. They complement each other well.

FAQ

How often should I write in my decision journal?

There's no set frequency. Write whenever you make a decision that meets your threshold (high stakes, irreversible, uncertain, or repeated). For most people, this means 2-4 entries per month. Quality matters more than quantity.

What if I don't have time to journal before every decision?

For truly urgent decisions, even a 2-minute voice memo counts. Capture your thinking in whatever form you can. For non-urgent decisions—which is most of them—the time spent journaling usually improves the decision quality enough to pay for itself.

Should I share my decision journal with anyone?

That's personal. Some people share entries with trusted advisors for outside perspective. Others keep it completely private, which allows for more honest self-assessment. Both approaches work. Consider sharing selectively—some decisions benefit from external input, others don't.

How long should each entry be?

As long as needed to capture your actual reasoning—usually 150-400 words. More complex decisions might require more. If entries are too short, you're probably not being specific enough. If they're consistently over 600 words, you might be overthinking the format.

What if I was wrong about a decision?

That's valuable data. Understanding why you were wrong teaches you more than confirming you were right. Approach review with curiosity, not judgment. Ask: "What can I learn from this?" not "How could I be so stupid?" Wrong decisions are the price of admission to better judgment.

Can I use an app for decision journaling?

Yes. Apps like Life Note can help by prompting reflection and analyzing patterns across entries. The key is finding a tool you'll actually use consistently. Some people prefer paper, some prefer digital—both work. The best tool is the one you'll actually use.

How is this different from keeping a decision journal template?

A template is a tool; this practice is what you do with it. The template structures your entries. The practice includes recording, reviewing, and learning over time. See our Decision Journal Template for a ready-to-use format.

How long before I see results?

You'll start noticing benefits within the first month—more clarity at the moment of decision, less rumination afterward. But the deeper benefits—calibration, pattern recognition, genuine improvement in judgment—take 6-12 months of consistent practice to develop. This is a long game.

Start Your Decision Journal Today

Think of one decision you're facing right now. Before you make it, open a document or notebook and write down:

1. What you're deciding
2. Why you're leaning in this direction
3. What you expect will happen
4. How you're feeling about it
5. When you'll review this entry

That's your first entry. You're now a decision journaler.

The best time to start was before your last major decision. The second best time is now.

If you want structured guidance, our Decision Journal Template gives you a complete framework for tracking and improving your decisions over time.

Related Resources

• Decision Journal Template: Track Your Choices & Improve Decision-Making
• The Complete Goal Journal Guide
• The Science of Goal Setting & Achievement
• Journaling Exercises for Behavior Change
• Self-Discipline Journal: 75+ Prompts & Techniques
• 30 Journaling Prompts for Self-Reflection