Operating Principle

2–4 min read

Every Plan Underestimates How Long Things Will Take

Every Plan Underestimates How Long Things Will Take

Every Plan Underestimates How Long Things Will Take

You will systematically underestimate how long this will take, no matter how carefully you plan it.

You will systematically underestimate how long this will take, no matter how carefully you plan it.

You will systematically underestimate how long this will take, no matter how carefully you plan it.

Reference-class forecasting beats inside-view optimism by anchoring timelines to comparable past projects.

Reference-class forecasting beats inside-view optimism by anchoring timelines to comparable past projects.

Reference-class forecasting beats inside-view optimism by anchoring timelines to comparable past projects.

Reference-class forecasting beats inside-view optimism by anchoring timelines to comparable past projects.

Operating Question

What evidence, base rate, or structural constraint should change this decision?

What evidence, base rate, or structural constraint should change this decision?

What evidence, base rate, or structural constraint should change this decision?

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Why It Matters

Reference-class forecasting beats inside-view optimism by anchoring timelines to comparable past projects.

Supporting Evidence

Daniel Kahneman and Amos Tversky on planning fallacy; Bent Flyvbjerg on overruns.

Research Notes

Treat this as a disciplined decision heuristic and account for relevant context and limits.

Practical Actions

Find comparable past projects; use their completion times; log estimates versus actuals.