Most managers make decisions and then move on. The good ones make decisions and then revisit them in their own mind. The best ones write it down.

A decision journal is exactly what it sounds like: a log of significant decisions, the context around them, what you expected to happen, and what actually happened. It's not a diary — it's an accountability tool and a learning machine. For managers, it also prevents a common failure: remembering only the decision and forgetting the tradeoff you accepted to make it.

The Format That Works

Not a stream of consciousness. A structured entry with these fields:

The decision: What did you decide? Be specific. Not "we decided to go with option A" but "we decided to hire a senior engineer before shipping v2 rather than after."

What you knew at the time: What information did you have? What did you believe about the market, the team, the competition? Don't editorialize — just capture.

What you expected to happen: Write this before you know the outcome. "My expectation is that this will reduce time-to-hire by 40% and allow us to ship v2 on schedule."

What actually happened: Come back to this in 60 or 90 days. What was the outcome? How does it compare to your expectation?

What you'd do differently: With the outcome in hand, what would you tell your past self? This is the learning. Don't skip it.

The Discipline of "Decide Before You Record"

Here's the trap: if you fill out the "expected outcome" field after you know the result, you're gaming yourself. You'll unconsciously adjust your prediction to match what happened. The value of the journal is destroyed.

The solution: after making a significant decision, write the first three fields immediately (decision, what you knew, what you expect). Lock it. Then set a calendar reminder to fill in the last two fields in 60 or 90 days.

This is genuinely uncomfortable. Do it anyway.

The Meta-Exercise: Quarterly Review

Once a quarter, read through your last 25 decisions. Not to judge them — to look for patterns.

  • Are you consistently overconfident or underconfident?
  • Are there categories of decisions where you're reliably wrong?
  • Where did you ignore good advice? Where did you fail to seek it?
  • Are there decisions that keep getting revisited because they were never fully owned?

These patterns are worth far more than any individual decision. They tell you where your decision-making system needs help — whether that's better input, different stakeholders, more time, or clearer criteria.

Henry Ward's Version

Henry Ward, who built the management infrastructure at eShare, used a version of this called "the decision memo" — every significant decision got a written record of the rationale and the expected outcome, visible to the whole company. This wasn't just for personal learning. It was for institutional accountability and knowledge sharing.

The version described here is private first. But if you run it well and build the habit, graduating to a shared decision log for your team — where they can see and learn from how you make decisions — is a powerful next step. Keep the private journal for raw thinking; use the shared log for decisions the team needs to understand, remember, or inspect later.

The journal is personal. The habit is the point. Start with just one decision this week.