business-case

name

business-case

description

Build a business case for a build/buy/defer investment decision — do-nothing always included as the baseline, benefits quantified as re-runnable calculations with confidence tags, full costs (build + run + opportunity), ranges instead of false precision, and the flip-assumption named. Use when the user needs to justify an investment, write a business case, compare build vs buy vs defer, or get budget/sponsor approval for an initiative.

business-case

Produces the document a sponsor can approve, challenge, or kill on its merits — because every benefit shows its arithmetic, every option includes the one nobody advocates for (doing nothing), and the case names the single assumption that flips the recommendation. Decides whether to invest; tech-comparison-matrix picks between technologies after, prd-draft captures requirements after, exec-summary compresses this doc for a board.

How to respond

1. Pin the decision and the decider. What exactly is being decided ("invest ~3 engineer-quarters in X" — not "improve our tooling"), who decides, and by when. Ask at most 2 questions, spent on the cost of the status quo ("what does the current state cost per month, in what units?") and the decision deadline. A business case without a named decision is an essay.

2. Always include Option 0: do nothing. Costed like every other option — the status quo has a price (ongoing pain, growing risk, deferred opportunity) and the case must beat it explicitly, not by assumption. Then 2–3 real alternatives (typically build / buy / partial-defer). Every option presented is one someone could genuinely champion; a lineup of two strawmen escorting the preferred option is theater, and reviewers smell it.

3. Quantify benefits as calculations a reviewer can re-run. Every benefit shows: the formula, each input with its source tag, and a confidence tag (high = measured data, medium = reasonable extrapolation, low = informed guess). ✅ "40 agents × ~20 min/ticket saved [data: time study] × 30 tickets/day → 18–24 FTE-hours/day, confidence: medium (assumes 75–100% of tickets touch the flow)" — ❌ "significant efficiency gains" — an adjective benefit is a benefit that didn't survive arithmetic.

4. Use ranges, never false precision. Three estimates multiplied together do not produce "327% ROI" — they produce a range, and the case says which end is likelier and why. State payback as a range too ("breakeven month 7–11"). Single-point outputs from multi-guess inputs are the most reliable sign a case is selling, not informing.

5. Cost all three layers, per option: build (people × time, the dominant and most-lowballed term — include ramp-up and the integration tail), run (infra, licenses, support burden, maintenance — the layer "buy" options hide in year 2+ pricing and "build" options hide in maintenance), and opportunity (what these people would otherwise ship — name the displaced thing, don't leave it abstract).

6. Name the flip-assumption. The sensitivity question, answered honestly: which single input, if wrong, reverses the recommendation? ✅ "The case rests on ≥60% agent adoption; below ~40%, Option 0 wins — adoption is [low confidence], so we propose a 4-week pilot before full commit." If no single assumption flips it, say which pair does. A case with no flip-condition is claiming certainty it cannot have.

7. Recommend one option, committally. The recommendation names the option, the reasoning in two sentences, what was given up (the strongest point of the runner-up, stated fairly), and any de-risking step (pilot, staged commit) tied to the flip-assumption. "It depends" is the analyst's job half-done; the decider can disagree with a recommendation, but they can't disagree with a shrug.

8. Lead with the ask. The first lines of the document: the decision requested, the cost, the headline benefit range, the deadline. ✅ "Ask: approve 3 engineer-quarters (~$210k loaded) for Option B; expected payback month 7–11; decision needed by July 1 to hit Q4 capacity." Emit with templates/business-case.md, one message.

Useful references in this skill

• templates/business-case.md — the skeleton: ask-first structure, option table, benefit-calculation blocks, sensitivity section

Quality bar

• Option 0 is present and costed. A case that doesn't price the status quo hasn't established there's a problem worth money.
• Every benefit is a re-runnable calculation with sourced inputs and a confidence tag. Reviewers check arithmetic; they can't check adjectives.
• Outputs are ranges; the case says which end is likelier. False precision fails the doc even when the direction is right.
• All three cost layers appear per option — build, run, opportunity — with the displaced work named, not waved at.
• The flip-assumption is identified and, where confidence on it is low, a de-risking step is proposed before full commitment.
• The recommendation is singular and the runner-up's best argument is stated fairly. A case that strawmans the alternative converts no skeptics.
• The ask is the first thing read — option, cost, benefit range, deadline, in under 40 words.

When to use this skill

• ✅ "Should we build this?" / "write the business case for X"
• ✅ Build vs buy vs defer with real money or quarters at stake
• ✅ Budget/headcount approval needs a document, not a hallway pitch
• ✅ A persistent "we should really fix this" needs its cost of inaction priced

When NOT to use this skill

• ❌ The investment decision is already made — go to prd-draft
• ❌ Choosing between technologies for an approved initiative — tech-comparison-matrix
• ❌ Compressing an existing case for execs — exec-summary
• ❌ Trivial cost ("should we buy a $400/yr tool") — the case costs more than the decision; just decide

Anti-patterns to avoid

• ❌ Omitting do-nothing. Every option looks good against an unexamined status quo — that's why it gets omitted.
• ❌ Adjective benefits. "Improved efficiency, better experience, reduced risk" — three claims, zero numbers, nothing a reviewer can challenge.
• ❌ False precision. "327% ROI" from three guesses. Ranges with a stated lean, always.
• ❌ Year-one costing. Build cost without run cost — the buy option's renewal pricing and the build option's maintenance both live in year 2+, which is where cases go to die.
• ❌ Sunk-cost scaffolding. "We've already invested 2 quarters" argues for nothing; the case is forward-looking from today's zero.
• ❌ Option theater. Two deliberately weak alternatives flanking the favorite. Reviewers notice, and the case loses its credibility along with the vote.
• ❌ Burying the ask. Page 4, paragraph 2, "in light of the above we suggest…" — the sponsor read the first five lines; the ask lives there or nowhere.