Agile 团队倾向于协作式的相对估算，而不是由一个人猜测工时。最常见的技术是 Planning Poker，并配合较轻量的方法，如 t-shirt sizing 和 affinity estimation，用于大批量项目的估算。
Planning Poker
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1. PO reads and clarifies the story
2. Each estimator privately picks a card (1,2,3,5,8,13...)
3. Everyone reveals at the same time
4. Outliers (highest + lowest) explain their reasoning
5. Discuss, then re-vote until close enough to agree
同时揭示结果可以防止锚定在第一个声音或最响亮的声音上。