Planning Fallacy

The tendency to predict that one’s own task will take less time than similar tasks have taken in the past.

• Ex: A student plans to write a paper the night before it is due because the last one took about three hours, and it takes seven.
• Ex: A family expects a kitchen remodel to take six weeks, and it takes four months.
• Ex: A city budgets two years for a new bridge, and it opens in five.

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Last updated: October 14, 2026 at 1:20 PM