Case Interview Formats

A guide to the 7 case interview formats the major consulting firms use, from Victor Cheng (author of Case Interview Secrets). Familiarity with each format matters so a candidate isn’t caught off guard simply because they didn’t know what to expect. See Management Consulting.

The 6 skill areas every format tests

Regardless of format, all case interviews test the same underlying skills (they also tend to appear in roughly this chronological order within a single case):

1. De-construct a very ambiguous problem into smaller sub-problems that are easier to solve.
2. Logically analyze each sub-problem.
3. Do math while analyzing — both precise math and estimation math.
4. Develop a hypothesis that explains why the client’s problem exists and how to fix it.
5. Determine what data is needed to prove or disprove the hypothesis.
6. Communicate the conclusion in a CEO-friendly style.

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The 7 formats

Format #1 — Traditional Candidate-Led Case

The interviewer (playing “the client”) poses an incredibly ambiguous question (“Should we enter the Latin American market?” / “We’re losing money — how do we fix it?”) and you solve the whole case from that starting point. You decide which questions are worth asking and determine the answers. Skills 1–6 flow naturally from one to the next. Used by LEK and Oliver Wyman (stable candidate-led processes).

Format #2 — Interviewer-Led Case (Stop & Go Style)

McKinsey’s signature format. Two distinguishing features:

• The interviewer (not you) decides which parts of the case matter, tells you which issue to tackle when, and asks specific questions expecting specific answers.
• The flow is abrupt — you jump around. The interviewer might ask which of 4 areas is most important, then say “Let’s tackle Area #4” regardless of your answer.

Still tests all 6 skills, but in a more artificial, non-sequential way.

Format #3 — The Written Case Interview

You’re given a lot of data as charts and PowerPoint slides (~20–40 slides), 2 hours to review it, then a test about the client company. Tests all 6 skills in written form. Bain has used this in some European offices (historically associated with Monitor).

Format #4 — The Group Case Interview

You and ~3 other candidates work as a team to solve a case. Tests all 6 skills plus your ability to collaborate respectfully. Tip: you do well by helping your “competitors” succeed, not by shooting them down. Historically Monitor’s format (Monitor was acquired by Deloitte; adoption uncertain).

Format #5 — The Presentation-Only Case

Used by BCG in certain rounds/offices (early signs of Bain too). First ~50% is written: you get a stack of slides, time to analyze alone (no interviewer in the room), and prepare a 6–10 page presentation. You both write and deliver it. The interviewer(s) then challenge everything (“Why did you conclude that? Did you consider X? What facts support this?”) to verify you actually did skills 1–5 well on your own before communicating (skill 6).

Format #6 — The Estimation Question

Tests only skill #3 (math). Roughly 1/6 of total interview time goes to math, and estimation is one way it’s tested. You numerically estimate a number — usually market size (“How many rubber tires are sold per year?” / “How much gasoline does a typical filling station pump on a Saturday?”) — via (a) a few assumptions and (b) math. Not just torture: clients routinely ask these to size whether an opportunity is “big” or “small.”

Format #7 — The Problem Solving Test

Not really a case — a math test of general math, numerical critical-reasoning, and data-interpretation skills. McKinsey’s is the McKinsey Problem Solving Test (McK PST); BCG has a similar “Potential” Test. Question types:

• Computation / word problems (e.g. prices +15%, costs +20%, units +15% → what’s profit?)
• Data sufficiency / interpretation (which conclusions does Chart Exhibit 1 support?)

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How to prepare — two schools of thought

Approach #1 — “Teach to the Test”: familiarize yourself with each format’s mechanics (timing, question style, scoring) and drill for it specifically.

Approach #2 — Master the 6 skill areas: get genuinely good at the underlying skills so you can handle any format.

Cheng leans heavily toward Approach #2. His reasoning: firms constantly change their recruiting processes — even different offices of the same firm experiment with different formats — so chasing the specific format is exhausting and brittle. His recommendation: spend ~80% of effort mastering the 6 skill areas, and ~20% familiarizing yourself with the specific format(s) you expect given the firms you’re interviewing with.

As of writing, the most stable processes were McKinsey (interviewer-led), LEK (candidate-led), and Oliver Wyman (candidate-led); Bain and BCG were revamping theirs.

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Source: Victor Cheng, Case Interview Secrets (CaseInterviewSecrets.com). Member links from the original (CaseInterview.com login, McK PST guide, BCG Potential Test guide, CaseInterviewMath.com) omitted as gated.