Why consulting, and why McKinsey, BCG or Bain: how to answer

What are interviewers listening for when they ask why consulting?

Most candidates hear this question as an invitation to say something impressive. The person across the table hears it as a cheap way to test three things at once, and after a few dozen interviews they can tell within twenty seconds which kind of answer is coming.

The first is motivation that belongs to you. Something narrower than a love of problems in general: a moment where you were doing something and wanted more of it. The second is knowledge of the job: do you know what a consultant does on a Tuesday, including the parts that are dull or tiring, or are you in love with the brochure. The third, which comes into play once the first two are in place, is fit with how this particular firm works. Ask a consultant why they chose their firm over the other two and you will usually hear a story about people and a way of working, rarely about a slogan.

The question usually arrives early, sometimes as your first words in the room, so it doubles as a small test of presence. Do you sound like someone talking, or someone reciting? An answer that is a little rough but clearly yours beats a smooth one that could be lifted from any forum post.

A note on sources before we go on. We are not affiliated with McKinsey, BCG or Bain, and interviewers differ by office and by day. What follows comes from having interviewed candidates ourselves, from the firms' own published material, and from candidate reports, which we flag as such. Where a firm-specific detail changes often, confirm it with your recruiter.

Which why-consulting answers sink candidates?

The weak answers share one property: the interviewer could hear them from anyone. That is a worse problem than being wrong, because there is nothing to push on, and an interview that cannot push on your answer moves on with a lower opinion of you and no evidence for a higher one.

• Prestige and reputation. It answers why this brand, not why this job, and the obvious follow-up is whether you would want the job at an unknown firm.
• Exit options. Everybody has thought about them and consultants know it. Leading with the door out is a poor pitch to someone deciding where to invest two years of training.
• Generic problem solving. “I love solving complex problems” fits an engineer, a chess player and a crossword addict equally well, which is the trouble with it.
• Reciting the website. Values and slogans quoted back to someone who works there tell them you read a page. They have read it too.
• Learning curve as the whole answer. It is true, it is half the applicant pool's answer, and it describes only what you would receive, never what you would give.

Some of these are fine as a supporting clause. Nobody will mark you down for saying you want to learn quickly. The trouble starts when one of them is the lead, because the lead is what the interviewer remembers.

How do you build a why-consulting answer from your own experience?

Most people write the sentence first and go hunting for a story to hold it up. Do it the other way round. Start with the evidence, find what it has in common, and let the answer be whatever the evidence supports. It takes an evening, and it is the only method we know that produces an answer nobody else could give.

Then say it aloud, twice, and record it on your phone. Written answers feel shorter than spoken ones. If yours runs past two minutes, cut the second story rather than speaking faster.

What does a weak why-consulting answer sound like next to a strong one?

Below are three rewrites. The candidates are illustrative, not transcripts of real people, and the strong versions are written the way a prepared but nervous person speaks: a few false starts, plain words, a caveat. Each runs 70 to 100 seconds aloud. They are longer than you might expect, because specificity takes words.

Rewrite one: from prestige and learning curve to a moment

Nothing here is false. There is also nothing to hold. The interviewer can ask “which industries?” or “what doors?” but neither question tests you, because the answer would be another generality. Try rewriting it before you look at ours.

Rewrite two: from generic problem solving to the last mile

Read it back and try substituting “banking”, “law” or “product management” for “consulting”. Nothing breaks, which is the diagnosis. The strong version picks a narrower claim, one only some careers satisfy.

Rewrite three: from the website to a conversation

This is the most common why-this-firm answer we hear, and it is a paraphrase of a careers page. Collaboration, innovation and global reach fit all three firms, so the interviewer learns nothing about why this one. The fix is a source the interviewer cannot find online, which means your own conversation with someone at the firm. A better adjective changes nothing.

Two details are worth copying. The candidate reports what she concluded from the conversation, not merely what someone said, and she volunteers a limit on what she knows. Both are cheap and neither sounds rehearsed. One warning: never imply a referral you do not have.

How long should the answer be, and what will the interviewer ask next?

Our position is 90 seconds to two minutes. At a normal speaking pace of 130 to 160 words a minute, that is roughly 200 to 320 words, which is about a page of double-spaced text. Some prep sources will tell you two to three minutes is acceptable, and it is, if every sentence carries something. Below about 60 seconds it sounds evasive. Past three, the interviewer has stopped listening and started composing the next question.

Then the follow-ups arrive, and this is where the answer is marked. These are the ones we have asked or heard asked, in roughly the order they tend to come:

• What did you like least about that project?
• Who else was involved, and what did they do?
• Who have you spoken to at the firm, and what surprised you?
• What do you think you would find hardest about the job?
• You could do this in industry. Why not?
• Why us and not one of the other two?
• What else are you considering, and why?
• What would make you leave consulting after two years?

A generic answer draws almost none of these, because there is nothing to pull on. A specific answer draws several, which feels like pressure and is in fact the interviewer being interested. Rehearse your two or three hardest follow-ups aloud with a friend or a coach until “what did you like least?” stops feeling like an accusation.

Not every interview asks the question at all. Candidate reports say some Bain offices run a first round with the CV hidden from the interviewer and little or no fit questioning, sometimes only “why consulting” or “why Bain”, with behavioural questions handled separately. Prepare the answer regardless, because you will be asked it somewhere in the process.

How do you answer why McKinsey, why BCG or why Bain?

Here is an unglamorous starting point: from the outside, the three firms are more alike than different, and interviewers know it. A first-year at any of them works in a small team on a client problem, under time pressure, towards a recommendation. If you tell an interviewer the firms are wildly different, they will ask you to explain, and few candidates can.

The differences you can credibly cite come from three places: what the firm says about how it works, how its interview is structured, and what people there told you. Between us we know McKinsey and Bain from the inside. We have not worked at BCG, so for that firm we lean on BCG's own published material. Everything below is hedged accordingly, and you should confirm it on the firm's site.

Two more points. Choose the firm reasons you can defend against “and what else did they say?”, and drop the rest. And speak well of the other two: candidates who disparage the competition sound as though they have not met anyone at the firm they are supposedly choosing. If you are interviewing at more than one, do not tell any of them it is your first choice unless it is.

Office and practice reasons work if they are true. “I want to work in the Madrid office because that is where my family is and where I would stay after two years” is a real reason and needs no dressing up. A practice or a published piece of work you have read and disagreed with, in one sentence, is better than a list of industries.

How do you research a firm by talking to its consultants?

Three conversations is the minimum we would aim for, twenty minutes each. Start with your university alumni network and career centre, then firm events, then a short, specific message to someone whose profile shows a route similar to yours. Ask for advice, not a referral, and keep it small enough that a busy person can say yes on their phone.

Write one sentence about each call, straight afterwards: what you learned that you could not have found online. Those sentences become the raw material for your why-this-firm reason. If two of them contradict each other, that is fine and useful. Firms are not uniform, offices differ, and one person's experience is one person's.

Ask what they dislike. People at these firms are generally happy to say, and it is the fastest way to find out whether the doubt you have written into your answer is a real one. Do not quote anyone by name in the interview unless you are sure they would not mind. “A consultant in one of your offices told me” is enough.

What else is in the fit interview, and how do Bain and BCG differ from McKinsey's PEI?

“Why consulting” is often the first minute of a longer conversation about you. The rest tends to circle four themes: who you are, what you have led, how you work with people, and what has gone wrong. Each has a known shape.

Tell me about yourself

This is not a recital of your CV. A shape that works is present, past, future: where you are now, two decisions that got you here, and why the next step points at consulting. Aim for 60 to 90 seconds. It should lead straight into “why consulting” so the two answers read as one story rather than two.

Leadership, teamwork and failure

Leadership questions ask what you did when nobody was in charge or when you were. The interviewer is listening for a direction you set, who followed, and what it cost. Teamwork questions ask about a person you found difficult or disagreed with. The trap is a story in which everyone else is scenery; name a teammate and say what they contributed. Failure questions want a real setback, not a humble-brag such as “I care too much”, and what you changed afterwards. The mechanics of being probed two or three layers deep are the same as in the PEI, so our McKinsey PEI guide is the place to practise them.

The practical difference is how you spend your stories. For a McKinsey-style interview, prepare a few stories in depth, because one will be pulled apart. For BCG and Bain, prepare a wider set you can tell briefly and a handful you can defend at length. Coaches on the candidate forums say that even when Bain moves the fit part to a different stage, the preparation is the same, and we agree.

What does the Track record and drive dimension reward?

In the MBB Ready rubric, Track record and drive is 25% of the overall score: self-direction, collaboration, depth, growth mindset and results delivered. It is the dimension your fit stories are marked on. Our 30-minute case has no behavioural part and cannot mark it, so the scorecard reweights; the 60-minute full interview includes a fit conversation and does mark it. The rubric is our own, modelled on the scorecards we used as interviewers, not any firm's internal document. Here are two of the five skills as the marker reads them.

The most common way to lose marks on self-direction is to describe a project you were assigned as though you had initiated it. Interviewers ask “whose idea was that?” and the answer decides the score. If the true answer is “my manager's, and I owned the analysis”, say that: it is still evidence of ownership, and it is credible.

Results are where candidates undersell. A story with no outcome sounds like activity, and “the project was successful” is not an outcome. Give the number and your share of it: the clinic delay falling from forty to twenty-five minutes is a result, and saying who changed the rota is what makes it yours. The neighbouring skill, depth, is about what happens when the interviewer pushes twice: numbers, names, and the difference between what you did and what the team did. Our scoring guide and full rubric show all five skills and their anchors.

We should say what this does not cover. An AI coach can hold you to the anchors above and probe your numbers, but it cannot tell you your story sounds like a cover letter in the way a friend who knows you can. Use both: rehearse with a person for tone, and with a coach for probing and marking.

How do you prepare your fit stories in practice?

By the end of a week you want a small bank of stories, each written as notes rather than a script (scripts get recited, notes get told), and each rehearsed against at least two follow-ups. The checklist below is what we would work through, in order.

Once the case skills are in place, book a run in which the fit part is scored rather than only practised. If you are heading to final rounds, our final-round guide covers how the two parts are combined, and our case interview mistakes page lists the errors that cost marks in the case half.