McKinsey, BCG and Bain interviews

Every MBB process has two conversations

Read the three careers sites side by side and the same shape appears. One interview tests how you take a messy business problem apart. The other asks what you have actually done, and how. McKinsey states that for most client-facing roles “you will participate in personal experience interviews and problem-solving interviews”. BCG describes step 2 of four as a “traditional interview” where “we will explore your experience, skills, and motivation for joining BCG”. Bain says interviews are customised to the role, that some roles include at least one behavioral interview, and that consulting roles run a digital assessment first and case interviews after.

Two things follow. Preparing only cases leaves half the process untouched; a BCG alumna quoted on the firm’s own site puts it plainly: “In all of your case prep, it can be easy to forget that BCG interviews also include a behavioral portion.” And all three firms say in writing that a case has no single correct answer, so memorising a framework to recite aims at the wrong target.

McKinsey: Solve, the PEI and the problem-solving interview

McKinsey describes Solve as “a gamified assessment that tests your natural problem-solving abilities” used for most consulting roles, and adds a line that candidates often do not believe: “There’s no need to prepare, just approach it with curiosity and creativity.” Applicants for technical roles may instead get a hands-on technical assessment covering areas such as programming, data analysis or system design.

For the Personal Experience Interview, the guidance is specific. McKinsey asks you to come prepared to discuss important experiences in detail, to “choose experiences which genuinely mattered to you”, to talk about your specific role, and to “lead with reasoning, not actions”. It then warns: “We want to see your authentic self, so be prepared to have a conversation, not to present a rehearsed story.” Leading with reasoning is the part most candidates miss. Saying what you decided and why you decided it, before listing the steps, is what the firm says it wants to hear.

The Problem Solving Interview is the case. McKinsey calls it a “typical McKinsey client scenario” and says it will “present a business case to evaluate your approach to solving complex problems”. The site publishes six practice cases with suggested answers: Beautify, Diconsa, Electro-Light, a case on transforming a national education system, Talbot Trucks and Conservation Forever. The firm says working through them will “help you become familiar with the types of questions we ask”. It also warns that there is not one logical solution, and that candidates should listen carefully and share tailored solutions rather than standard frameworks.

BCG: four steps and what interviewers look for

BCG’s process page is unusually concrete about sequence. Step 1 is the application. Step 2 is the skills interview, your chance “to go beyond your resume”. Step 3 is the case interview, used for client-facing roles. Step 4 is a team interview, which BCG says also assesses “problem-solving, analytical, and communication skills”.

The firm lists five qualities its consulting interviewers look for: integrity, intellectual curiosity, creative thinking, a collaborative mindset and drive. That list beats any question bank as a preparation checklist, because it tells you what each story you pick has to demonstrate.

BCG’s case interview preparation page describes the task as working through a realistic business challenge step by step: “structure your approach, ask thoughtful questions, analyze data, perform quick calculations, and identify the most important factors”. It then gives two short lists. The do list is listen actively, be yourself, think structurally, communicate clearly, clarify assumptions and show your thinking. The do-not list is panic under pressure, rush your response, overcomplicate solutions, ignore feedback, stay silent and interrupt.

One detail is worth stating accurately, because it is often searched for. BCG’s current careers pages do not publish an online case assessment stage or a public interactive case library. They offer a job simulation called OneDay@BCG, described as giving “insights into the challenges we solve”, plus blog posts from a talent acquisition director and a consultant on what the interviews feel like.

Bain: digital assessment first, then the case

Bain is the most explicit of the three about assessments. Candidates for intern and full-time consulting roles may be required to complete a digital assessment, delivered through either Sova or Test Gorilla, and you are told which one by email after you apply. It takes roughly 30 to 40 minutes and reflects skills such as problem solving, communication and analytical thinking.

The practical notes matter. A pen, paper and calculator are allowed. The Test Gorilla version needs no preparation and should be done in one sitting; the Sova version can be split across sittings and has a preparation area with sample questions. AI assistance is prohibited, along with recording, screenshots and any software that transcribes or gives feedback.

On the case itself, Bain reframes the whole exercise: it is a structured conversation about a real business problem, and the firm is not looking for a single right answer but for how you think, structure problems and build on ideas. It also says plainly that case interviews are used for consulting roles only. Two of its own practice cases are on the site: Coffee Shop Co., where you help a friend decide whether opening a coffee shop is a good idea, and FashionCo., where you advise a fashion business on declining revenues.

Bain’s interviewing page adds something the other two do not promise. All candidates for the same role get identical questions in order to reduce bias, and any feedback you receive is based on an objective scoring system.

Practising the case the way the firms describe it

Take the published advice literally and a practice routine falls out of it. Read the prompt back in your own words and confirm the objective before you say anything else. Both BCG and Bain list clarifying the objective and the assumptions as a do, not a nicety.

Then structure out loud. Say what the two or three parts of the problem are, in what order you want to look at them, and why that order. This is the moment candidates reach for a memorised framework, and McKinsey’s instruction to share tailored solutions rather than standard frameworks is a direct warning against it.

Do the arithmetic slowly and narrate it. BCG asks for quick calculations but also for clear communication, and a number nobody can follow is worth nothing. State your assumption, state the units, then compute. If you notice an error, say so and correct it: a corrected mistake costs far less than a confident wrong number.

Finish with a recommendation and the one thing that would change your mind. A case conversation that ends on analysis instead of a decision reads as unfinished.

For material, use the firms’ own cases first: McKinsey’s six published cases with suggested answers, and Bain’s Coffee Shop Co. and FashionCo.

The experience side: choosing stories that hold up

Four or five stories cover almost everything these interviews ask: one where you led without formal authority, one where you decided with incomplete information, one where you disagreed with someone and handled it, one where something went wrong, and one where you changed a group’s mind.

Write each in a few lines, not a script, and be ready for the follow-up chain these firms use: what were the options, why that one, what did you give up, what happened, what would you do differently. McKinsey’s phrase is the test to apply to your draft: are you leading with reasoning, or just narrating actions?

Specificity is the differentiator. “The team improved the process” says nothing. “I noticed we were re-entering the same figures in two places, proposed a single source, and got the change agreed in one meeting by showing the error rate” says what you did and how you think.

BCG’s five qualities are a useful filter: map each story to at least one of integrity, intellectual curiosity, creative thinking, collaborative mindset and drive. If a story maps to none, it is probably not the story to tell.

Finally, prepare questions for them. A BCG consultant quoted on the firm’s site says the questions you ask at the end “can really help you understand if you are a fit”, and McKinsey tells candidates directly to bring questions.

What the firms say about using AI while you prepare

This is now part of the published rules, and the lines are clearer than most candidates assume. McKinsey’s careers site splits it into a short list. Polishing your resume or practising interview questions is marked as encouraged, as is asking AI to explain concepts or frameworks while you prepare. Exaggerating or creating achievements that are not yours is marked as not allowed. So is generating real-time answers during an interview, and so is using AI during assessments unless specifically permitted. The firm’s reasoning is quoted directly: “We want to get to know you, not your AI tool.”

Bain is stricter about the assessment itself, prohibiting AI tools and asking that you complete it without the assistance of others. BCG publishes separate pages on using AI in your application and on how it hires with AI. The practical reading: rehearse with these tools, close them before the interview starts, and never submit a claim you could not defend under a follow-up question.