金大哥 - business-case Skill 详情

Overview

This skill provides a rigorous framework for building an investment thesis. It forces the identification of explicit assumptions, calculation of ROI, and the simulation of worst-case scenarios to ensure that capital and resources are allocated only to initiatives with a clear path to "Sufficiency."

Iron Law

NO BUSINESS CASE WITHOUT EXPLICIT ASSUMPTIONS AND SENSITIVITY ANALYSIS Uncertainty is inherent in business, but failing to model it is a choice. A business case that assumes a single linear outcome is a fantasy. You must simulate "The Plan Not Going According to Plan."

State Machine

digraph business_case_flow {
    "Discovery: Objectives" [shape=doublecircle];
    "Step 1: Define Sufficiency & ROI" [shape=box];
    "Step 2: Map the 5 Parts" [shape=box];
    "Gate: Viable Economics?" [shape=diamond];
    "Step 3: Sensitivity Analysis" [shape=box];
    "Step 4: Audit Opportunity Cost" [shape=box];
    "Case Approved" [shape=doublecircle];

    "Discovery: Objectives" -> "Step 1: Define Sufficiency & ROI";
    "Step 1: Define Sufficiency & ROI" -> "Step 2: Map the 5 Parts";
    "Step 2: Map the 5 Parts" -> "Gate: Viable Economics?";
    "Gate: Viable Economics?" -> "Step 3: Sensitivity Analysis" [label="viable"];
    "Gate: Viable Economics?" -> "Step 1: Define Sufficiency & ROI" [label="failed"];
    "Step 3: Sensitivity Analysis" -> "Step 4: Audit Opportunity Cost";
    "Step 4: Audit Opportunity Cost" -> "Case Approved";
}

When to Use This Skill

When requesting additional budget or headcount.
When evaluating a potential new market entry.
When deciding between two competing strategic paths.
When an existing project is underperforming and needs a "worthwhile to continue" check.

When NOT to Use This Skill

For minor tactical experiments (use A/B testing).
For pure brand awareness tasks where direct ROI cannot be measured.

Core Process

Step 1: Define Sufficiency & ROI

Define the exact revenue, user, or outcome level at which the initiative becomes "worthwhile to continue."

Projected ROI: Ratio of Net Profit to Total Investment.
Runway & Burn: Calculate the monthly cash consumption and the time remaining until the next capital event. (Source: Kaufman, Ch. 5; Feld, Ch. 3)

Step 2: Map the 5 Parts of Business

Justify how the initiative addresses:

Value Creation: Which Economic Values (Speed, Efficacy, Status) are we satisfying?
Marketing: How will we reach the 95% mainstream market, not just early adopters?
Sales: What is the Allowable Acquisition Cost (AAC)?
Value Delivery: How will we satisfy customer expectations predictably?
Finance: Is the Lifetime Value (LTV) greater than the AAC? (Source: Kaufman, Ch. 1; Gil, Andreessen interview)

Step 3: Sensitivity Analysis & Doomsday Scenario

Apply a "Margin of Safety."

Sensitivity: How does ROI change if growth is 50% lower?
Doomsday: Simulate the failure of your most critical assumption. If the company collapses because this one project fails, the risk is too high. (Source: Housel, Ch. 5; Kaufman, Ch. 7)

Step 4: Audit Opportunity Cost & Interaction

Opportunity Cost: Explicitly list the projects that are not being done to make room for this one.
Interaction: How does this initiative impact existing business units? (e.g., Will it cannibalize our core product?) (Source: Kaufman, Ch. 5; Bacon, Ch. 6)

Step 5: Define OKRs

Set one Objective (WHAT) and 3-5 Key Results (HOW).

Quality Safeguard: Pair every quantitative KR (e.g., "$50M Revenue") with a quality KR (e.g., "<5% Churn") to prevent short-term reckless behavior. (Source: Doerr, Ch. 4)

Cross-Skill Invocations

REQUIRED SUB-SKILL: problem-framing — to ensure you are solving the right problem before investing. RECOMMENDED SUB-SKILL: decision-frameworks — to help weigh the subjective trade-offs identified in the audit.

Rationalization Table

| Thought | Reality | |---------|---------| | "The numbers speak for themselves." | Numbers are projections based on assumptions. The assumptions speak; the numbers just listen. | | "We've already spent $1M, we can't stop now." | Sunk cost fallacy. Only future ROI matters for the decision to continue. | | "We'll figure out the economics after we scale." | Scale without unit economics is just a faster way to go broke. | | "Our competitor is doing it, so we must too." | Social comparison leads to copying outlier behavior that may not be repeatable for you. |

Red Flags

These thoughts mean STOP — you are about to shortcut:

"This project is 'too big to fail'" → It's actually a fragile, high-risk bet with no margin of safety.
"We don't need unit economics yet" → You are planning a "mercenary" crash, not a "missionary" success.
"The plan is 100% solid" → You have ignored "The Plan Not Going According to Plan."

Diagnostic Checklist

[ ] Has a "Sufficiency" point been defined (when to stop vs. when to double down)?
[ ] Is every output goal paired with a quality/counter-effect goal?
[ ] Does the case include a worst-case sensitivity simulation?
[ ] Has the opportunity cost (deferred projects) been explicitly named?
[ ] Is the "Main Job" of the customer clearly identified as the value driver?

Sources

Kaufman, Josh. The Personal MBA. Ch. 1, 5, 7, 11.
Gil, Elad. High Growth Handbook. Marc Andreessen & Claire Hughes Johnson interviews.
Doerr, John. Measure What Matters. Ch. 1, 4.
Feld, Brad. Venture Deals. Ch. 1, 3, 4.
Housel, Morgan. The Psychology of Money. Ch. 2, 3, 5.
Bacon, Carl R. Practical Portfolio Performance. Ch. 1, 4, 5, 6.