Investment & Finance
ProCircle of Competence
能力圈 · Source: Warren Buffett / Charlie Munger
Honestly assessing your true depth of understanding in a domain before making a major commitment
Core Concept
Your circle of competence is the domain you truly understand — not what you think you understand, but where you can make precise judgments under pressure. Munger: "Knowing what you don't know is more useful than being brilliant." Act within your circle; be cautious or decline outside it.
✓ When to use this
Before investing, partnering, founding, or making cross-domain decisions. Honestly draw the boundary of "what I truly understand" — bet bigger inside, assume you will be wrong outside and either size down or buy outside expertise.
✗ When not to use this
Not for pure exploration and learning phases — deliberately stepping outside is how the circle expands. Also do not use this to rationalize over-conservatism; avoiding all unfamiliar things shrinks the circle.
Questions you will be asked
Using this framework, you will work through —
- 1.What domain does this decision require you to deeply understand?
- 2.How deep is your genuine understanding of this domain? Where did you acquire it?
- 3.Can you explain the most complex aspects of this domain in simple language? Try it.
- …and 3 more
Worked example
Expand to see what a filled-in run looks like
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Worked example
Expand to see what a filled-in run looks like
Situation
朋友是 AI 領域創業者，邀我投資他的種子輪 100 萬。我自己是消費品產業出身，對 AI 商業模式只是「看新聞了解」。
1. What domain does this decision require you to deeply understand?
是否投 100 萬到朋友的 AI 新創。
2. How deep is your genuine understanding of this domain? Where did you acquire it?
我的能力圈：消費品（10 年）、零售通路（5 年）、品牌行銷（深度）、財報分析（中等）。
3. Can you explain the most complex aspects of this domain in simple language? Try it.
能力圈外：AI 技術門檻、模型訓練成本結構、GPU 供應鏈、AI 護城河本質、competitive moats 在 AI 產業如何成立——這些我都答不出來。
4. What don't you know in this domain? What are the known unknowns?
我能評估的：朋友本人（信任、執行力）、他的早期客戶（消費品角度）、他的單位經濟（如果適用）。我評估不了的：技術領先程度、5 年後是否被大模型公司碾壓。
5. Does this decision's required understanding fall inside, on the edge, or outside your circle?
從圈內看：朋友本人值得信任 → +；早期客戶屬於我懂的領域 → +。從圈外看：技術可持續性我不懂 → 風險未知。
6. Based on your honest assessment, what is your decision? If outside your circle, how will you handle it?
降低倉位：投 30 萬而不是 100 萬。把這當作「下注朋友的人」而不是「下注 AI 趨勢」——若失敗能承受、若成功小有回報。
Use it inside ChatGPT / Claude
Paste the prompt below and the AI will walk you through this framework, one question at a time.
你現在是引導使用者做「能力圈評估」的教練（Buffett / Munger）。 依序問： 1) 你正在考慮的決策是什麼？（投資、合作、創業、跨領域） 2) 誠實圈出你的能力圈——你能在多深的層次回答這個領域的問題？（具體到「能 vs 不能」） 3) 這個決策的關鍵變數中，哪些在你能力圈內？哪些在圈外？ 4) 圈外的部分，你能找到可信的外部專業者協助嗎？ 5) 即使有外部協助，你還是無法判斷的剩餘風險是什麼？ 6) 基於能力圈內外比例，你的倉位/承諾大小應該調整嗎？ 特別提醒：在圈內加碼，在圈外降低倉位或退出——這比「假裝什麼都懂」更可靠。 互動規則： 1. 一次只問一題，等使用者回答後再進入下一題。 2. 使用者答完所有題目前，不要做總結或下結論。 3. 若答案太抽象、太籠統，請追問一次具體例子或數字後再繼續。 4. 全部答完後，輸出三段：(a) 摘要使用者的關鍵判斷；(b) 你看到的盲點或張力；(c) 一個具體下一步行動建議。 5. 不要替使用者做決定，只把判斷攤開讓他自己決定。
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FAQ
How do I know where the edge of my competence is?
Three tests: (1) Can you clearly explain the core logic of this field to a non-expert? If you can't put it in simple words, you're likely familiar with the concepts but don't really understand. (2) Can you accurately name "the mistakes I'd make in this field"? People who really know can articulate their own failure patterns; people who don't will say "I'm fine across the board." (3) How many real surprises and failures in this field have you experienced? Without being knocked around by reality, you're likely still on Dunning-Kruger's peak.
Should I expand the circle or stick within it?
Buffett and Munger's answer: "The size of the circle doesn't matter — knowing where the edge is does." Practical principle: "expand slowly, cross borders with caution" — use the core circle as base camp, run small experiments near the edge (low-stakes tests), and only annex an area once you genuinely understand it. The real danger isn't a small circle — it's the blind spot of "thinking you understand when you don't," because that's when you bet big in an unfamiliar domain — Buffett's "going all-in where you have no idea," which loses almost every time.
How does Buffett apply circle of competence in practice?
Buffett hasn't invested outside his circle of competence in 50+ years — which is why he missed early Google and Amazon. Asked if he regrets it, his answer: "No, because if I'd invested it would have been luck, not judgment — and next time I might lose much more." He treats the circle as "the source of decision authority" — only acting where he can fully explain. This discipline matters more than any single investment: avoiding "cross-border disasters" is far less damaging than missing "cross-border opportunities."
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