DAY OF INTERVIEW
You have practised 30 cases.
Then the interviewer says, “Ready?”
And somehow your first structure feels like you have never seen a case before.
Your skill did not disappear.
You may simply be starting cold.
A case interview asks you to switch quickly into a very particular mode: speak crisply, calculate under pressure, structure ambiguity, and explain where your thinking is going. Fifteen minutes will not teach those skills.
It can make them easier to access.
You do not need another case... you need to activate the right machinery
The mistake is using your final 15 minutes to solve as much as possible.
A full practice case introduces too many variables. You can get stuck, discover a strange industry, make an arithmetic error, or start second-guessing your frameworks.
That is not a warm-up.
That is another performance.
- speaking clearly
- structuring one ambiguous question
- doing a short calculation
- synthesising an answer aloud
Wake up the motions. Not the anxiety.
For a deeper look at getting your voice ready before the interview begins, read Improving Vocal Warm-Up Before Consulting Interviews.
Minutes 1 to 5 look almost too easy... until you hear the difference
Start by talking.
Not about consulting. Not about your PhD.
Read a paragraph aloud, explain what you ate for breakfast, or summarise yesterday's case in 30 seconds.
The point is to stop your first complete spoken sentence of the day from happening in front of a McKinsey, BCG, or Bain interviewer.
Then give yourself a simple prompt: “A university wants to increase research-industry partnerships. What would you consider?”
Take 60 to 90 seconds and build a structure.
Do not judge it.
You are starting the engine.
Minutes 6 to 10 are where PhDs often overcomplicate things
Now do arithmetic.
But resist the urge to choose the hardest mental-math drill you can find.
- percentage change
- break-even
- multiplication or division with round numbers
Write the equation first. Calculate cleanly. State the implication.
That last step matters.
A case interviewer is rarely impressed because you found “24.” They care whether you realise that 24 means the client clears its hurdle rate, misses its target, or needs another 6 units.
Math ends with a “so what?”
If numbers are the part most likely to feel rusty under pressure, use Case Interview Mental Math for a deeper practice routine.
The final five minutes may feel like stopping too early
Now synthesise.
Take any simple situation and give yourself 30 seconds:
“Based on what we know, I would recommend X for two reasons. First... Second... The main risk is...”
Do that twice.
Then stop.
| Warm-up instinct | Better move | What you are activating |
|---|---|---|
| Full case | One structure | Problem decomposition |
| Hard calculations | Three clean calculations | Numerical fluency |
| Memorise PEI | Speak naturally aloud | Verbal rhythm |
| Read frameworks | Give two syntheses | Answer-first communication |
The goal is not to enter the interview feeling intellectually exhausted.
It is to make “case mode” feel familiar before anyone starts evaluating you.
Your 15 minutes are finished.
Now close the notes.
The next problem should come from the interviewer.