Psychology & Behavior
ProPlanning Fallacy Check
規劃謬誤檢查 · Source: Daniel Kahneman / Amos Tversky
Counteracting systematic over-optimism when estimating time, cost, and resources
Core Concept
When planning future projects, people almost universally underestimate time, cost, and difficulty while overestimating completion probability. This isn't a personal flaw — it's a built-in cognitive bias. The antidote is the "outside view": look at statistical outcomes of similar past projects rather than the internal details of this one.
✓ When to use this
When estimating project completion time, launch dates, time-to-profitability. Humans systematically underestimate time and cost — especially when enthusiastic about the plan, this check should be forced.
✗ When not to use this
Highly standardized work with reliable historical timelines (production lines, packaged services) does not need this check. Also do not use it to rationalize over-pessimism — inflated estimates harm equally.
Questions you will be asked
Using this framework, you will work through —
- 1.What is your plan or commitment? What are your original time and cost estimates?
- 2.What historical data from similar projects can you find? What were their actual outcomes?
- 3.Based on this external data, what would be a more realistic estimate?
- …and 3 more
Related Frameworks
Psychology & Behavior
Inside View vs Outside View
Planning and forecasting — especially when you're overly optimistic about your own project, goals, or capabilities
Psychology & Behavior
Base Rate Forecasting
Decisions requiring outcome forecasts — from startup success rates to investment returns, start by asking "how does this type of thing typically go"
Management & Thinking
Pre-mortem
Stress-testing a plan before committing — finding failure paths you haven't seen yet