When you plan, you naturally adopt the inside view: focusing on your specific intentions, resources, and obstacles. The story feels controllable.
But plans are vulnerable to optimism, selective memory, and wishful timelines. You imagine the best path and treat it as the default.
The outside view breaks the spell. It asks: what happens to similar projects in the real world? How long do they take, how often do they fail, and by how much do they overrun?
This approach can feel cold, even demoralizing, because it replaces narrative with statistics. Yet it is often the only way to counter the planning fallacy.
If you want better forecasts, step outside your story. Let the base rate speak first, then argue with it only on evidence, not on hope.