Planning fallacy

What is it?

Planning fallacy is when plans are built around the ideal version of how things will go. You may assume the task will take less time, require fewer steps, involve fewer interruptions, or demand less energy than it actually does. This creates chronic lateness, overcommitment, missed deadlines, and frustration because the plan wasn’t designed for real life. The issue isn’t optimism by itself; it’s failing to include friction, transitions, rest, uncertainty, and the fact that future-you will have limits.

How do people work on it?

Use real-life planning, not best-case planning. When estimating, ask: “How long has this taken before?” “What steps am I forgetting?” “What usually interrupts this?” “What energy level will I actually have?” Then add a buffer. For anything important, build in at least 25–50% more time than your first estimate, especially if the task is new, emotional, administrative, or multi-step.

A useful exercise: use a hidden-steps check. Before starting a plan, list every tiny step involved. “Go to appointment” might include shower, clothes, finding insurance card, travel, parking, waiting, forms, appointment, payment, travel back, decompression. Planning improves when invisible steps become visible.

Additional resources to explore: CBT for adult ADHD, ADHD coaching, and organizational-skills training can help with planning, time management, and breaking tasks into realistic steps. Organizational-skills interventions have been associated with improvements in organization, time management, and planning.