Mind Insight
Back to Glossary
Understanding the Mind

Planning Fallacy

Planning Fallacy

The planning fallacy is the tendency to optimistically predict that a task will be completed faster and more easily than it actually will be. It's an extremely common cognitive bias that nearly everyone experiences at some point.

Details

What is the Planning Fallacy?

The planning fallacy is a concept first proposed in 1979 by psychologists Daniel Kahneman and Amos Tversky. It refers to a systematic bias in which people underestimate the time, cost, and effort required for a future task while overestimating the likelihood of success.

Why Does the Planning Fallacy Happen?

Mindy is here to explain. The main reasons the planning fallacy occurs include:

  • Inside view bias: We focus only on the specific details of the current plan rather than drawing on past similar experiences.
  • Optimism bias: We tend to ignore the possibility that obstacles or unexpected problems will arise.
  • Motivational factors: The desire to finish quickly clouds our realistic judgment.

    • The Planning Fallacy in Everyday Life

    If you've ever thought a report would take one day but it ended up taking three, or assumed an hour would be enough for cooking only to spend over two hours in the kitchen — you've experienced the planning fallacy firsthand.

    How Can We Reduce It?

  • Use an outside view: Look back at how long similar tasks actually took you in the past.
  • Build in buffer time: Adding 30–50% extra to your estimated time makes for a more realistic plan.
  • Break it into steps: Dividing a big goal into smaller units helps you predict the time needed for each stage more accurately.

    • Connection to Mental Well-Being

    Frequently experiencing the planning fallacy can lead to self-blame and frustration. But this is not a reflection of your lack of ability — it's a natural cognitive tendency that everyone shares. Mindy reminds you that being gentle with yourself is what truly matters.

    💡 Real-Life Example

    Planning to study for an exam in just two days, only to find it actually takes a full week, is a classic example of the planning fallacy.

    Ad

    Want to talk more about "Planning Fallacy"?

    Mindy is here to explore this topic with you and offer personalized advice

    Related Psychological Tests

    Explore tests related to this topic to understand yourself more deeply

    This content is for educational purposes and does not replace professional medical diagnosis.

    Planning Fallacy (Planning Fallacy) | 마음스캔 심리학 용어사전