Quotation
Last reviewed:
“Amos and I coined the term planning fallacy to describe plans and forecasts that are unrealistically close to best-case scenarios.”
Daniel Kahneman · Thinkers beyond philosophy · Modern · 2011; the term is older, from his work with Amos Tversky
What does it mean?
The planning fallacy is a forecast stuck near the best case. They coined the name for that pattern, and for the improvement that comes from looking at similar cases rather than at the story of this one. The usual reading is the inside view against the outside view: your plan in your head, versus the record of plans like it. A competing reading thinks the fallacy is mere pessimism about all plans. He is not against planning. He is against a best case that has not met a base rate. The sentence is chapter 23. The curriculum story in that chapter is the example. The definition is the sentence.
Did Daniel Kahneman really say this?
The library’s label is Well attested. His English in chapter 23, where he retells the curriculum project that taught him the outside view. He and Tversky had named the fallacy earlier. This sentence is the book's definition. No page is pinned here because editions shift; the chapter is stable.
Where it comes from
Thinking, Fast and Slow (2011), chapter 23, The Outside View
Approximate date: 2011; the term is older, from his work with Amos Tversky.
How to use it
A kitchen extension in Bristol that you expect to finish in six weeks, because the best week of the job looks like that, is the fallacy if similar jobs ran long. Ask someone for the distribution, not for encouragement. The outside view feels ruder than the plan. He thinks it is the correction.
A mindset reading
Best case is allowed as a hope. It is not yet an estimate. The library's planning-fallacy entry is this idea in shorter form, and the profile links it.
Understand the philosophy
Chapter 23 is 'The Outside View'. The key term is planning fallacy, a name he shares with Tversky. Chapter 7's smooth story is how the best case becomes the plan. Overconfidence, chapter 20, is the feeling that goes with it. The bias entry in this library uses the same name and the same cure: look up similar cases.
- mind
- knowledge
FAQ
What does it mean?
The planning fallacy is a forecast stuck near the best case. They coined the name for that pattern, and for the improvement that comes from looking at similar cases rather than at the story of this one. The usual reading is the inside view against the outside view: your plan in your head, versus the record of plans like it. A competing reading thinks the fallacy is mere pessimism about all plans. He is not against planning. He is against a best case that has not met a base rate. The sentence is chapter 23. The curriculum story in that chapter is the example. The definition is the sentence.
Did Daniel Kahneman really say this?
Well attested. His English in chapter 23, where he retells the curriculum project that taught him the outside view. He and Tversky had named the fallacy earlier. This sentence is the book's definition. No page is pinned here because editions shift; the chapter is stable.
Which work is it in?
Thinking, Fast and Slow (2011), chapter 23, The Outside View Approximate date: 2011; the term is older, from his work with Amos Tversky.