Write Down What You Expected Before You Find Out

Without a record made in advance, you will remember having predicted whatever happened.

Memory reorganises itself around outcomes. Once a decision has played out, the reasoning that supported it becomes either obviously sound or obviously foolish, and the genuine uncertainty you felt at the time disappears from the record. This makes experience a much weaker teacher than it should be. Ten years of decisions produce ten years of confidence and comparatively little learning, because the raw material for learning, which is the gap between what you expected and what occurred, was never written down.

The remedy is unglamorous and takes minutes. When you make a decision of consequence, write a short note: what you are deciding, the two or three outcomes you expect, roughly when you expect to know, and what would tell you this was wrong. Keep the notes together. Read the old ones on a set rhythm, quarterly is enough. The point is not to grade yourself. It is to discover the specific shape of your own error, which is remarkably consistent and completely invisible without a record.

Most people find the same handful of patterns. They are optimistic about how quickly people will change behaviour. They underestimate what it costs to stop doing something. They are more accurate about numbers than about relationships, or the reverse. Knowing which of these is yours is worth more than any general advice, because it tells you where to add a deliberate correction and where to trust yourself. It also gives you something honest to say to a board when a decision goes badly, which is a considerably stronger position than surprise.