Consulting Interview Prep

The consulting case interview tests a single core skill above all others: structured problem decomposition. MECE — Mutually Exclusive, Collectively Exhaustive — is the organizing principle. A MECE breakdown divides a problem into categories that don't overlap (mutually exclusive) and together cover every possible dimension (collectively exhaustive). Without it, you end up with either double-counting or blind spots.

This matters because consulting work is fundamentally about organizing complexity. A client comes to McKinsey with "our profits are declining." That problem could have a hundred causes. The consultant's job is to build a framework that structures the space of possible causes into distinct, testable hypotheses — then systematically eliminate the wrong branches until only the real cause remains. The case interview simulates this in 30 minutes.

The common mistake is using generic frameworks as formulas: "I'll use a profitability framework: revenue minus cost." That works as a starting point, but interviewers at McKinsey, Bain, and BCG are looking for you to customize the framework to the problem. A profitability decline in a hospital network requires a framework tailored to healthcare economics — payer mix, procedure volume, reimbursement rates — not the same tree you drew for a retail chain.

The highest-value skill: before you start a case, tell the interviewer your framework structure and ask for a moment to organize your thinking. That 30-second pause produces better performance than immediately generating ideas.