Business Analyst interview question
How do you build a business case?
A business case compares a credible baseline with options using benefits, costs, risks, dependencies, timing, assumptions, and sensitivity. Recommend the option with measurable outcomes and a plan to validate them.
Direct answer
What a strong answer covers
How it works
A business case makes a decision comparable: it states the problem and a credible baseline of what happens if nothing changes, then lays out two or three options with their benefits in money or measurable outcomes, their one-off and recurring costs, the risks and dependencies of each, the timing of benefits, and the assumptions everything rests on. A sensitivity check shows which assumptions matter most, and the recommendation names the option, the metrics that will show whether it worked, and when they will be reviewed. Honesty about uncertainty is what makes the case trusted.
Example
The case for replacing a manual reconciliation process compared do nothing at 1.5 FTE per year and rising error fines, a scripted fix at 40,000 in effort saving 0.8 FTE, and a vendor platform at 120,000 plus 30,000 per year saving 1.4 FTE with audit features. Sensitivity showed the vendor option only won if volumes grew 20 percent, so the recommendation was the scripted fix with a review at twelve months against the volume forecast.
Common mistakes
- Presenting one option against a baseline of zero instead of the real status quo.
- Counting soft benefits as cash without saying how they will be measured.
- Hiding the assumptions the whole case depends on.
A useful answer structure
Answer from your own work.
Do not memorise a script: use only examples you can explain honestly in follow-up questions.
Open the desktop workspace and rehearse a clear answer in your own words.