Forecasting · interactive demo
What Happens When You See the Reference Class?
Estimate a project from the inside view, then compare it with a version that includes how long similar work actually took.
Question
Does adding a reference class change a delivery estimate built from an ideal step-by-step plan?
This is an educational demonstration, not a scientific measurement of you. One response cannot show that a bias caused your choice.
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Random condition
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Evidence-reviewed lens
Planning Fallacy
The planning fallacy is a well-documented tendency for people to predict their own task completion times too optimistically. The effect has been observed across different kinds of tasks, but it is not a rule that every plan will run late. Project overruns can also come from changing scope, dependencies, incentives, poor data, deliberate underestimation, or genuinely unusual events, so a late project should not automatically be diagnosed as a planning fallacy.
Why We Underestimate How Long Work Will Take · Project estimation & delivery
How to interpret this
This is also an intervention demo: the outside view does not prove your first estimate was biased, but it adds evidence the inside view can miss.
Better check: Start with comparable completed work, then explain why the current case should be faster or slower.