Prompt: Write a One-Page Business Case
A prompt for a business case that states the actual costs, benefits and risk of doing nothing — not just an optimistic pitch.
The prompt
You are a business analyst who has to defend this case to a sceptical finance team.
Objective: Write a one-page business case for {{THE PROPOSAL — e.g. adopting a new tool, hiring a role, changing a process}}.
Context: The problem this solves is {{THE ACTUAL PROBLEM}}. The rough cost or investment required is {{COST OR EFFORT}}.
Constraints:
- State the cost of doing nothing, not just the benefit of acting
- Every benefit claimed needs a rough number attached, even if it's an estimate labelled as such
- Include at least one real risk or downside — a business case with no risks is not credible
- Maximum one page (roughly 400 words)
Output format: Return sections for Problem, Proposed Solution, Cost, Expected Benefit, Risk, and Recommendation, each 2–4 sentences.
Before finishing, check that every benefit has a number or an explicitly labelled estimate attached, and that a real risk is stated.
Example
Input
THE PROPOSAL — e.g. adopting a new tool, hiring a role, changing a process: adopting a shared project-management tool across the team THE ACTUAL PROBLEM: tasks are currently tracked in five different spreadsheets, and status updates take a weekly meeting to reconcile COST OR EFFORT: roughly £3,000 a year in licensing, plus an estimated two days of setup time
Output
Problem Tasks are currently tracked across five separate spreadsheets, so status is never in one place and reconciling who is doing what takes a weekly meeting. The cost of doing nothing is that meeting continuing indefinitely: an estimated 5 person-hours a week, or roughly £6,500 a year at an estimated £25 an hour. Proposed Solution Adopt a single shared project-management tool that the whole team updates directly. It replaces the five spreadsheets and removes the need for the weekly reconciliation meeting. Cost Approximately £3,000 a year in licensing. Setup and migration take an estimated two days, roughly £400 in staff time at the same estimated £25 an hour.
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Expected Benefit Removing the weekly reconciliation meeting saves an estimated 5 person-hours a week, worth roughly £6,500 a year. That is an estimate, not a guarantee, and it depends on the team actually using the tool. Risk Adoption could stall if the team doesn't consistently update the new tool. That would leave both systems running in parallel, creating more confusion rather than less. Recommendation Adopt the tool for a 3-month trial before committing to the annual licence. That confirms the team actually uses it before the larger spend.
Why it works
- Requiring a number on every benefit, even a labelled estimate, forces the same rigour a real business case needs to survive finance scrutiny.
- Requiring a stated cost of doing nothing counters the default bias toward describing only the upside of acting.
- A mandatory real risk stops the case reading like marketing copy, which is usually why business cases get rejected on credibility alone.
Why the basic version fails
“Write a business case for X” tends to produce an upbeat pitch with vague benefits (“improves efficiency,” “boosts morale”) and no acknowledgment that saying no also has a cost. Finance teams see through this instantly.
What this prompt fixes
Requiring a number on every benefit — even a rough, labelled estimate — forces the same discipline a real business case needs. Requiring a stated risk stops the output from reading like marketing copy, which is usually why business cases get rejected on credibility alone.
Tips per model
- Claude is good at stating estimates as estimates rather than presenting a guess as a fact — important for anything going in front of finance.
- ChatGPT sometimes needs a nudge to include a real risk; if the first draft’s risk section feels token, ask it to be more specific about what could actually go wrong.