Anyone can tell you a case interview is “an hour of business problem-solving”. This free lesson shows you one. You read the same briefs a candidate reads, watch a setup exchange play out turn by turn, then follow the structure, the sparring and the synthesis that turn a messy prompt into a recommendation — the full arc, one beat at a time. It is the widest-angle view of case interviewing we teach, and the fastest way to know whether this format is for you. Read it signed-out; if you want to keep going, a free account saves your place.
Start the free lesson → What’s inside Chapter: 1 · How the case works · Format: interactive, reads like a lesson · Cost: free, no card A sample of the first brief in this lesson, shown as it reads in the lesson. /learn · a sample of the lessonPrompt
Prompt phase
Start this lesson →The lesson walks five phases — the same rail every Case Ace case lesson rides. Exhibits build on the page as you read: brief cards, a live transcript, buckets and slots.
PromptThree real briefs land one after another — a gym chain losing members, a portfolio question, a market entry. Same length, same vagueness as the real thing.
SetupA worked setup exchange: the questions worth asking, the ones that waste a minute, and how the good ones sharpen the brief.
StructureThe candidate’s plan takes shape — buckets that don’t overlap, a priority, and a first hypothesis worth testing.
ExploreThe analysis sparring: what the numbers say, what they don’t, and where the interview pushes back.
RecommendSynthesis — the answer, the so-what, and the next step stated like a consultant, not a student.
The other free lessons: Case interview frameworks → Case interview math →Nearly every case interview, at McKinsey, BCG, Bain or anywhere else, travels the same five stages: the prompt, the setup, the structure, the exploration and the recommendation. Knowing where you are in that sequence tells you what the interviewer is listening for, and stops you answering a question that has not been asked yet.
The case opens with a short brief read aloud. Before you think about frameworks, decide what kind of problem the client has, because the brief tells you what your first job is. Three shapes come up again and again.
Write down the client, the question and any numbers in the brief. Then name the tension in one line: what makes this hard rather than obvious.
Next you ask a few clarifying questions. They are not a formality; each should change how you would build the structure. Ask about the objective (is it profit, revenue, share, or something non-financial?), the timeframe, and anything in the brief you do not understand, such as how the business makes money. Two to four questions is usually right.
Then restate the case in a sentence before you move on. A restatement catches misunderstandings while they are still cheap, and it shows the interviewer you have heard the brief rather than matched it to a template.
Ask for a moment, build a structure on paper, and walk the interviewer through it. A structure is a plan for how you will answer the question: the three or four areas you will investigate and what you would want to know in each. For Summit Fitness, a good structure looks at revenue quality (members, price, churn), the cost to serve each member, and whether growth has outrun capacity. Those branches are specific to a gym; a generic “revenue and costs” tree would not have found the churn.
Finish by saying which branch you would start with and why. That choice is often the first thing the interviewer marks.
Most of the case happens here. The interviewer hands you exhibits, asks for calculations and invites ideas. Three habits carry this stage.
If you get lost, return to the structure and the question. Interviewers expect the middle of a case to be messy, and they reward candidates who steer back on their own.
The case ends with the interviewer asking what you would tell the client. A strong recommendation has four parts, in this order.
Take a position even when the data is incomplete. “I would recommend X, and the thing I would check first is Y” is a consultant’s answer; “it depends” is not.
McKinsey cases are usually interviewer-led: the interviewer asks a set series of questions and you answer each in turn. BCG and Bain cases are more often candidate-led: after the structure, you decide what to look at and ask for the data you need. The five stages are the same in both. In a candidate-led case you also drive the order, so the habit of naming your next step out loud matters even more.
Case Ace’s AI interviewer runs every case like this lesson — questions, exhibits and a scored report. Case Ace has 46 full AI-interviewed cases and 221 quick-fire drills across 45 lessons.
The first part of the lesson is open to everyone. Create a free account — ten seconds, email or Google/Microsoft — and the whole lesson opens, your spot is saved, and the other free lessons are waiting.