Case study question
Your dashboard says online sales last month were £2.4 million, but the finance team’s report says £2.2 million. How would you find out why the two figures differ, and what would you do about it?
What they’re really asking
Numbers that don’t match are an everyday problem for analysts, and how you handle them affects whether people trust your work. The interviewer wants a methodical approach: assume both figures could be right by their own definitions, then compare what each includes and when each counts a sale. Building a step-by-step bridge from one number to the other is the key technique. Finishing with what you’d change, so the gap doesn’t confuse people again, shows you think beyond the one-off fix.
How to structure your answer
- Size the gap£200,000, about 8%. Ask whether it’s new or has always been there.
- Compare definitionsVAT, refunds, discounts, cancelled orders, delivery charges and which sales count as online.
- Compare timingOrder date or payment date, the cut-off at the end of the month, and when each source was last updated.
- Build a bridge and fix the causeExplain the gap step by step, agree one definition and label the dashboard clearly.
For more on answering this kind of question, including the mistakes to avoid, read our guide to case study questions.
An example outline
This is an example outline, not a script. Use it to see the shape of a strong answer, then build yours from your own experience, in your own words.
- Frame
- A gap of £200,000, about 8%. First I’d ask finance how their figure is built, and check whether the gap shows up every month.
- Definitions
- Say the dashboard counts orders when they’re placed, before refunds. Finance counts sales when they’re paid, after refunds and cancellations.
- Bridge
- Start at £2.4 million. Take off £120,000 of refunds, £50,000 of orders cancelled before payment, and £30,000 of timing: orders placed at the end of the month but paid in the next. That reaches £2.2 million.
- Check
- Reconcile a few single days line by line, to make sure each step is real and nothing else is hiding in the totals.
- Fix
- Agree with finance which figure is used for what, rename the dashboard total “orders placed”, add a net sales figure that matches theirs, and check the gap every month.
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Read the guide
Last reviewed 28 September 2026 by the Deeplink Interview team. How we write and check our questions.