McKinsey: format, Solve, and the PEI

Intuition

McKinsey runs the most structured, standardized interview of the big three, and that structure is a gift if you know it's coming. The case feels less like a free-flowing conversation and more like a guided tour: the interviewer asks a structuring question, then a math question, then shows an exhibit, then a brainstorm, each scored somewhat independently. On top of the case sits two distinctive McKinsey features: the digital Solve assessment up front, and the famously deep PEI behind the case.

Knowing the format means you're never surprised by the next turn, you just need to nail each station.

Framework

What's distinctive about McKinsey:

• Interviewer-led case. They drive. Expect discrete questions: frame the problem, do a calculation, interpret an exhibit, brainstorm ideas. Answer each crisply and let them steer.
• Solve assessment. A gamified digital test (ecosystem-building, simulations) screening problem-solving before or alongside interviews. Practice staying methodical under a timer.
• The PEI (Personal Experience Interview). Deep probing of one story per theme, leadership, personal impact, conflict. They want your specific actions, not the team's. Prepare 2–3 rich stories you can go five layers deep on.
• Top-down communication. Lead with the answer (Pyramid Principle), McKinsey prizes it.

Worked Example

In a McKinsey round you might: (1) get a structuring prompt, "what would drive a hospital's profitability?", and present a tailored tree; (2) be handed an exhibit and asked for the insight; (3) do a margin calculation live; (4) brainstorm ways to cut wait times; then (5) switch to the PEI: "Tell me about a time you led a team through resistance." They'll probe relentlessly, what exactly did you say, what was the pushback, what did you personally decide? Treat each station as its own crisp performance.

Here's the difference one station makes. Handed a revenue exhibit, the weak candidate narrates: "Revenue grew until 2023, then declined about 10%." True, and worth nothing, the interviewer can read. The strong candidate leads with the insight: "The headline is that the entire decline sits in the hospital segment, pharma and labs actually grew, so I'd want to know what changed in hospital pricing or contract renewals that year." Same chart, thirty seconds, and one of them just demonstrated top-down communication while the other described axes.

In the room

Three phrases earn instant credit at McKinsey. On any recommendation: "My recommendation is X, for three reasons", answer first, always. On any exhibit: "The headline from this chart is…" before a single detail. In the PEI: "What I personally did was…", the word "we" is where PEI stories go to die. The format trap to avoid in the moment: fighting the interviewer-led structure. When they cut off a thread you loved and pivot to a brainstorm, that's not a sign you failed, it's the format working as designed. Drop the thread instantly, answer the question asked, and hand control back. Candidates who say "before I answer, can I just finish my earlier point…" read as uncoachable. Station-by-station crispness, answer-first delivery, and "I" statements under pressure are the three tells McKinsey interviewers compare notes on afterward.

Pitfalls

• Trying to "take over" an interviewer-led case, answer the question asked, then hand it back.
• Bringing a thin PEI story you can't defend under five rounds of "and then what did you do?"
• Underestimating Solve, it's a real screen, not a formality.