What Is a Case Interview?
A case interview is a live problem-solving exercise in which a candidate works through a realistic business problem together with the interviewer, such as why a client's profits are falling or whether a retailer should enter a new market. Instead of reciting prepared answers, the candidate asks clarifying questions, lays out a structure, runs quick math out loud, and reasons through to a recommendation, usually within 20 to 40 minutes.
The format is the signature of consulting recruiting because it mirrors the job itself: consultants break ambiguous problems into pieces, test hypotheses against data, and defend recommendations to clients. McKinsey, BCG, and Bain, collectively known as MBB, run multiple case interviews across two or more rounds, and most other strategy and Big 4 advisory groups use some version of the same format.
How a Case Interview Unfolds
Most cases follow a predictable arc. The interviewer reads a short prompt, the candidate asks a few clarifying questions, then takes a moment to lay out a structure: the two to four buckets of analysis that would answer the question, such as market attractiveness, competition, economics, and execution. From there the conversation moves through analysis, interpreting charts or data tables, running numbers aloud, and stating what each finding implies for the client.
There are two common styles. In interviewer-led cases, typical at McKinsey, the interviewer steers the candidate through a set sequence of questions; in candidate-led cases, typical at BCG and Bain, the candidate drives the analysis and decides what to examine next. Both end the same way: the interviewer asks for a recommendation, and the strongest candidates answer directly, giving the recommendation first, then two or three supporting reasons and the key risks.
A Worked Example: Falling Profits
Suppose the prompt is that a regional coffee chain's profits fell 20% last year, and the client wants to know why and what to do. A structured candidate splits profit into revenue and cost, then breaks revenue into price times volume. Asking for data reveals that prices and store count are flat but volume per store is down 15%, which points to a demand problem rather than a cost problem.
Quick math keeps the answer concrete: if each store served 200,000 customers at an average ticket of $5, revenue per store was $1,000,000, so a 15% volume drop removes $150,000 per store while rent and labor stay largely fixed, which is why profit falls much faster than sales. The candidate might hypothesize that a new competitor is pulling traffic, ask what changed in the local market, and close with a targeted recommendation, such as loyalty pricing and faster service, supported by that volume math.
Why Case Interviews Matter for Recruiting
Cases are the make-or-break hurdle of consulting recruiting: candidates typically face four to six of them across first and final rounds, and a weak case performance usually ends the process regardless of resume strength. Interviewers grade structure, comfort with numbers, business judgment, and communication, which together answer one question: would they trust the candidate in front of a client after a few months of training.
Preparation is a skill built out loud, not by reading. Serious candidates practice structuring problems verbally and complete dozens of live cases with partners, whether classmates, consulting club members, or former consultants, because pacing and poise only come from repetition. Memorized frameworks are easy for interviewers to spot, and clear, MECE logic tailored to the specific problem plus a confident, direct recommendation consistently beat a recited template.
