Investment & Finance
ProScenario Planning
三情境規劃 · Source: Shell / Strategic Planning
Systematically evaluating worst, base, and best outcomes under high uncertainty
Core Concept
Don't build just "my plan" — build three simultaneously: worst case (bear), most likely (base), best case (bull). Forcing yourself to plan for all three means you won't be caught off guard by any outcome, and it makes you more honest about expected value.
✓ When to use this
When the future is highly uncertain and a single forecast is untrustworthy. Build optimistic / base / pessimistic scenarios with response plans for each — more resilient than betting on one forecast, more flexible than over-hedging.
✗ When not to use this
Not for short-term decisions with narrow outcome ranges — multi-scenario analysis inflates unnecessary uncertainty. Also do not use it to indefinitely defer decisions; after three scenarios, action must land.
Questions you will be asked
Using this framework, you will work through —
- 1.What is the core uncertainty in this decision? What variable's direction most affects the outcome?
- 2.Worst case (Bear): If the key uncertainties all move against you, what happens?
- 3.Base case (Base): What is the most likely scenario? What probability do you assign?
- …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
創業第二年，公司現金流還剩 14 個月（不算下一輪募資）。經濟環境不穩，要規劃明年策略。
1. What is the core uncertainty in this decision? What variable's direction most affects the outcome?
明年的策略走向——成長優先 vs 收益優先 vs 保守過冬。
2. Worst case (Bear): If the key uncertainties all move against you, what happens?
樂觀：經濟回穩、A 輪如預期完成（拿到 $3M，現金延長到 24 個月），客戶留存提升。動作：加聘 4 人、投廣告、加快產品線。
3. Base case (Base): What is the most likely scenario? What probability do you assign?
基準：經濟維持現狀、A 輪延 6 個月才完成（現金壓到 8 個月）、客戶緩慢成長。動作：維持現有 headcount、聚焦核心產品、現金管控。
4. Best case (Bull): If everything goes well, what's the result? What probability?
悲觀：A 輪失敗、要靠營收撐 12+ 個月。動作：立即減 30% 燒錢、砍非核心產品、集中現有付費客戶、bridge round 從 angel 找。
5. In the worst case, what is your response plan? Can you survive it?
三情境的觸發指標：A 輪 term sheet 是否在 Q1 內談下、月留存率是否 > 85%、廣告 LTV/CAC 是否 > 3。
6. Calculate weighted expected value: (worst×prob) + (base×prob) + (best×prob) = ? What is your decision?
預設走基準情境，準備好悲觀情境的「fire drill」——一旦觸發指標亮紅燈，3 週內切換動作模式。樂觀情境的擴張動作只在實際看到指標後才啟動。
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「三情境規劃」的策略教練（Shell / Royal Dutch Shell）。 依序問： 1) 你要規劃的決策或時段是什麼？ 2) 樂觀情境：什麼條件成立會走到這個情境？對應的動作是什麼？ 3) 基準情境：最可能發生的版本？對應動作？ 4) 悲觀情境：什麼條件惡化會觸發？對應動作？ 5) 觸發指標：用什麼可觀察的指標來判斷你正走向哪個情境？ 6) 預設走哪個情境？備好哪個情境的「即時切換包」？ 特別提醒：三情境不是平均，是準備——每個情境要有具體動作清單，當指標觸發就執行。 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。
Related Frameworks
Management & Thinking
OODA Loop
Making fast, effective decisions in rapidly changing or highly uncertain situations
Management & Thinking
Pre-mortem
Stress-testing a plan before committing — finding failure paths you haven't seen yet
Management & Thinking
Second-Order Thinking
Complex decisions with cascading effects, strategic choices, any "obvious" decision — because first-order outcomes everyone sees are often already priced in
FAQ
How is scenario planning different from a pre-mortem?
Scenario planning builds three futures at once — worst, base, best — and prepares a plan for each, aiming to cover the distribution of outcomes; a pre-mortem digs deep into just the failure future to find its causes, aiming at the root of a single failure. One is broad (sweeping across possibilities), the other deep (drilling into failure).
Why plan the best-case scenario — isn't defending the worst case enough?
Because the best case needs preparation too: explosive growth, a demand surge, a window suddenly opening — unprepared good news can crush you just as easily (servers crashing, quality collapsing, no time to hire). The value of three scenarios is being unflappable whatever happens, not just surviving the bad news.
How do I keep the three scenarios from becoming "optimistic / pessimistic / vague middle"?
Tie each scenario to concrete trigger indicators and corresponding actions, not emotional adjectives. Anchor the base case with a base rate (how this kind of thing usually goes); give the worst and best each an explicit "if I see signal X, switch to this scenario's plan" condition. The value isn't in the description — it's in pre-deciding "when I see this, I do that."
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