How to practise cases with a friend (and actually improve)

Practising with a friend is the best preparation you can get for a case interview, short of the interview itself. A real person across the table adds pressure, interrupts and asks follow-ups in ways no book can. But a lot of peer practice ends with a vague "yeah, that was good" and no clear idea of what to work on next.

A few habits change that.

1. The interviewer should hold the facts back

If the candidate gets the whole case pack up front, they're reading, not interviewing. The interviewer should release each fact only when the candidate asks a question that would reasonably uncover it. This is uncomfortable for both people the first time. It's also exactly how real interviews work.

2. Hints are allowed, but count them

Getting stuck is part of the practice. A good interviewer offers a nudge ("what else could drive revenue per customer?") instead of the answer, and notes that a hint was used. Over a few weeks, the number of hints you need is one of the clearest signs of progress.

3. Score skills, not the overall feel

"Good case" isn't feedback. Score the separate skills instead:

Structure: was the breakdown clear, complete and non-overlapping?
Hypotheses: did they test ideas, or ask for data at random?
Quantitative analysis: was the maths set up and explained correctly?
Business judgment: did they connect the numbers to what's really happening?
Communication: did they signpost and summarise as they went?
Recommendation: was the ending clear, supported and actionable?

The lowest score is what the next session should work on.

4. Switch roles, every time

Interviewing is underrated practice. When you hold the full case and watch someone else work through it, you see what a strong structure looks like, and what makes the interviewer lose the thread. Most people find their own cases improve after a few sessions on the other side of the table.

5. Keep the transcript

Memory flatters you. A record of what was actually said, which questions unlocked which facts and where the hints came, makes the debrief honest and specific.

lowercase builds all of this into a session: the interviewer gets a console with facts, hints and the full issue tree, the candidate sees only what they've uncovered, there's a six-part rubric at the end, and a single click swaps the roles.