Decision journal for leaders: how to start and what to log

A decision journal is a simple notebook where you write down a choice before you know how it will turn out. You record what you picked, why, what you expect, and when you will check. Months later, you compare your notes with what happened. That is how you learn whether your judgment is improving or you were just lucky.

Why leaders keep one

Memory is a poor record. Once a result is known, most of us believe we saw it coming. A good result makes the reasoning look sharp. A bad result makes it look careless. Neither is always fair.

Annie Duke, a former professional poker player, wrote about this in her 2018 book Thinking in Bets. Her point is that a decision and its outcome are two different things. You can choose well and still lose, because chance plays a part. You can choose badly and still win. If you judge only by results, you may copy a bad habit that got lucky or drop a sound habit that got unlucky.

A written note fixes that. It shows what you knew and believed on the day you chose. Nobody can rewrite it later, including you.

Sources: Annie Duke, Thinking in Bets (2018), the book's main argument about separating decision quality from outcome quality.

Why a written record beats good intentions

Leaders know that biases exist. Awareness alone does not seem to help much. In "Before You Make That Big Decision," published in Harvard Business Review in June 2011, Daniel Kahneman, Dan Lovallo and Olivier Sibony said that popular books have made executives aware of biases, but that awareness has done little to improve business decisions.

The article names several common traps. Confirmation bias leads people to ignore evidence that does not fit what they already believe. Anchoring gives too much weight to one piece of information, often the first number you hear. Loss aversion makes people too cautious.

The authors focus on spotting these traps inside a decision, before it is made. A journal gives you a place to do that. When you must write your reasons down, weak ones are easier to see.

Sources: Daniel Kahneman, Dan Lovallo and Olivier Sibony, "Before You Make That Big Decision," Harvard Business Review, June 2011 (hbr.org/2011/06/the-big-idea-before-you-make-that-big-decision).

A five-line template you can start today

Keep it short. If an entry takes more than five minutes, you will stop. Use these five lines for each decision that matters.

1. The choice: what you decided, in one sentence, and the date.
2. The reasons: the two or three facts or beliefs that tipped it.
3. The alternatives: what else you considered, and why you said no.
4. The expectation: what you think will happen, with a rough chance. For example, "about 70 percent likely to hit target."
5. The review date: a day on the calendar when you will check the result.

Add one more line if you can: how you felt. Tired, rushed, excited or under pressure from a senior person. These notes often explain a miss better than the numbers do.

The editors designed this template as a practical routine. It is our own shortlist, not a method taken from either source above.

What counts as a decision worth logging

Do not log everything. You will drown in notes. Choose choices that are costly to undo, affect other people, or are made with limited information.

• Hiring, promoting or letting someone go.
• Entering a new market or dropping a product.
• Large spending, such as a new system or a new office.
• Picking a partner, supplier or investor.
• Changing a team structure or a process others rely on.

Two or three entries a week is plenty for most leaders. A single strong entry is better than ten rushed ones.

How to review your entries

On the review date, open the entry and write what actually happened. Then ask two questions. First, was the result better or worse than I expected? Second, was my reasoning sound given what I knew then?

The second question is the harder one. It follows Duke's idea. A bad result with sound reasoning may call for no change. A good result with weak reasoning is a warning, not a win.

Once a quarter, read your last ten or twelve entries in one sitting. Look for patterns. Do you set your odds too high? Do you skip alternatives when you are busy? Do you lean on the first number you were given? Pick one habit to change and write it at the top of the next page.

If you lead a team, you can share a few entries with trusted colleagues. Asking them to challenge your reasons, not your character, makes the habit stronger. Keep private entries private.

Sources: Annie Duke, Thinking in Bets (2018); Kahneman, Lovallo and Sibony, Harvard Business Review, June 2011. The review questions and the quarterly routine are the editors' own suggestions.

Common mistakes to avoid

Most journals fail for a few simple reasons.

• Writing after the result is known. Always write at the time of the choice.
• Writing vague reasons such as "it felt right." Name the facts you relied on.
• Skipping the odds. A rough number is better than none.
• Never reviewing. A journal you do not reopen is only a diary.
• Editing old entries. Add a new note below instead and leave the original alone.

Start with your next real decision this week. Write the five lines, set the review date, and put it in your calendar.

Sources: editors' practical guidance, drawing on the two sources named above.