BCG Case Interview: Preparation Advice from a Former-BCG Consultant

I’ll first cover what all top consulting firms want, and then color my answer with some BCG green. Do not skip the first part if you’re not familiar with it though – these things matter tremendously and honing on the specifics for the BCG case interview is pointless if you’re not at the bar yet on the basics. 

What All Top Consulting Firms Expect 

All firms are looking for the same basics: smart people, able to think fast, accurately, creatively, and by themselves, and communicate the solutions they come up with concisely and eloquently. They are looking for people who are open to feedback, care about making an impact, are inspiring leaders to others, and thrive when working in teams. 

The entire point of the case interview and the behavioral interview is to test precisely these skills. If you’re not familiar with these yet, the case interview is a business problem that you solve in real-time with prompts and data from the interviewer, while the behavioral interview is an opportunity for you to showcase soft skills such as leadership or impact through relating past experiences. 

My colleague Rebecca (former McKinsey) dives a lot deeper into the basics of the case interview in our Guide to Case Interview Prep and also gives a few tips about the Behavioral Interview. It’s worth reading these if you haven’t already. 

As you go through the interview, you are graded independently and methodically on all these skills to allow for easy comparison across candidates. At the end of the day though, the question the interviewer is answering internally is: “Would I want to staff this person on my team?” It’s that simple. 

What BCG Emphasizes More Than Bain & McKinsey

All the firms care about the attributes below. Moreover, one thing my time in consulting convinced me of is that there is still more variation within firms than across firms in terms of personalities and style, so each interviewer will have slight skews in preferences on what they deem most important in a candidate based on who they’d like on their team. 

That being said, here are 3 things that were regularly important in BCG recruiting decisions during my time there: 

1. Drive
2. A Tailored Approach
3. The BCG Attitude

#1 – Drive

The most important thing to ace your BCG case interview is your ability to drive the case. This means always being in the driving seat as you go through the case interview: 

• knowing where to go next, 
• getting there by yourself, and 
• explaining to the passengers (i.e. the interviewer) where to, why, and exactly what they need to know about it. 

One way to do this is the “hypothesis-driven” approach that BCG talks a lot about, which simply means having a running hypothesis and driving toward testing it. For instance, once you are done laying out the structure of the case, do not wait for the interviewer to tell you what to do and take an initiative: 

Example: “My hypothesis at this point is that the profit decline is due to a change in our client’s pricing since you mentioned attendance remained stable. Do we have any data on the pricing and membership model our client used over the last 5 years and have there been any recent changes?”

Drive is not just the ability to know what to do next and move toward it smoothly, it’s also the ability to constantly explain why you are doing it. It shows your interviewer that you have both the ability to think well and take someone by the hand through your thought process as you do so. 

Example: “Now that we’ve established the revenues of our site each year, I’d like to compute the total cost to know whether these revenues are enough for our client to meet their target of breaking even in 2 years. Do we have any data on costs at this point? Maybe starting with investment costs?”

Why Is Drive So Important?

Because that’s what you need to do constantly on the job.  As a consultant, your clients are paying your team a lot of money so they expect to know exactly what you are doing with that expensive time and why. It also helps prevent you from taking any wrong turn, as they are still the experts on their own business. 

As a team member, your manager’s stress level will also go down by a lot if when they come out of the meeting, they hear you say that given the partner’s remarks you took the initiative to stress-test the results of the analysis you are showing the client tomorrow. They’ll know they don’t need to constantly tell you what to do: you’ll know what’s needed and you’ll be a good communicator about what you are focusing on so they don’t need to obsess over monitoring you either. 

Drive also means knowing what to do with the results you find, and spontaneously getting to what we call 2nd level insight. 

1st level insight: Using the result to answer the question you were asked. Example: “The total cost is $1.2M.Therefore, given the revenues we computed earlier, it will take us 3 years to breakeven.” 

2nd level insight: The next-step that pushes the problem-solving forward. Example: “This does not match our client’s objective of breaking even in 2 years, so at this point, we’d have to recommend that they do not enter this market. Before doing so though, I’m wondering if we could explore additional revenue streams to see if they can make this a viable opportunity. Is it ok with you if I take a moment to brainstorm options?”

By getting to 2nd-level insights, you show you’re not just an analyst. You’re a consultant and you have the skills to do everything for the client if you had to. 

I once saw a documentary about the recruiting process for the acrobatic show Cirque du Soleil. One applicant was told “Power went down, everybody else is injured, you’re the Cirque tonight. What do you do?” Some days on the job will feel exactly like that. That’s why you need drive.

#2 – A Tailored Approach

The second thing that is emphasized at BCG is the ability to tailor your approach to the situation at hand. As explained earlier, BCG is proud of coming to each client and business problem not with a pre-made solution, but with all their expertise and a commitment to developing what is best for the client in that case. This trickles down to the BCG case interview.

During the case interview, your structure will still rely on some basics that you might have seen in a book, such as “external/internal factors.” But as way you lay out your structure, and as you interact with the interviewer throughout the entire case, you are putting yourself in the shoes of a consultant that’d be visiting a plant, the client’s headquarters, or talking with the Vice President of Sales about their rollout strategy for this new left-handed stapler to address the situation at hand. 

You can foster that skill for yourself by “using the words of the case.”

Example: Don’t say “volume is going down” but “the number of cases ordered by the supermarket went down so we’ve been shipping fewer bottles.’ Ask clarifying questions about the business model of the client during the opening of the case: imagine that you are trying to understand how your best friend is making a living. The hypothesis-driven approach is also helping you tick that box. 

Similarly in any brainstorming question during the BCG case interview (for which you should also answer using buckets/a mini-structure by the way), use specifics of the case to structure your brainstorming.

Example: If asked about additional revenues opportunities, you could think about it each step along the customer journey of your client’s clients, or you could use “options within the client’s expertise area” vs. “options in adjacent areas” vs. “options in new areas of expertise.”

The goal is really to show your interviewer that you are not just a machine at rehashing models and frameworks. You know how to look at every situation with new eyes, and you’ll be able to catch the subtleties of each client.  

#3 – The BCG Attitude

Last but not least is the attitude you project. I just came up with the term “BCG attitude” so no need to Google it, but what I mean by it is a combination of being personable, being coachable, and having a go-getter mindset. 

In conversations among interviewers, I’ve seen candidates who did quite well on the case interview being disfavored compared to others because they failed to demonstrate these qualities. The logic is that if the interviewer does not feel comfortable having you represent them and BCG in front of the client or if they think you wouldn’t get along with the rest of your teammates (or that your teammates wouldn’t get along with you), there are plenty of other stellar candidates that day who would be a better fit.

Being personable. I don’t mean being a stand-up comedian or as charismatic as Barack Obama, simply that interacting with you is pleasant. The interviewer can naturally start chit-chatting with you, and ideally, as you go through the interview both you and the interviewer get the feeling of working together.

Anything perceived as arrogance is likely to be a turn-off for the interviewers: they don’t want to send someone who would project that vibe to a client. If you stay professional and make the effort to care about whoever is in front of you, you’ll be just fine.

Being coachable. Like other consulting firms, BCG has a feedback-heavy culture. You are constantly reviewed (upward and downwards, i.e. by both your managers and the people you manage, if any). There is a culture of sharing feedback directly and regularly (there is even a culture of discussing how you like your feedback to be given to you). Hell, that’s how you progress in these firms. 

It’s not that you’re not expected to know everything when you start: it’s that you’re expected to not know most things, and be able to learn them fast, and then get feedback, and then course-correct even faster. So someone who does not take feedback well is unlikely to thrive in that environment. 

In practice, try not to ignore cues the interviewers might be giving you on where to go during the BCG case interview. Abstain from showing annoyance at any point. 

Having a go-getter attitude. This means always being game for more if need be. 

On the job example: The team is exhausted. It’s already late Thursday, we have a presentation tomorrow. The client just completely changed their mind on what they want to see. Your manager doesn’t want to be worried about you throwing your laptop at the wall or being passive-aggressive in the windowless team room. 

Instead, being able to take a breath and say: “Ok, it is what it is. What do we need to do and how can we do it efficiently so that we still get to sleep?”

Of course, all of these soft skills are hard to measure. But if you collapse when you realize that your numerical answer was off by a factor 100, the interviewer might have less faith in your ability to endure and perform under pressure. If that happens, just acknowledge it, explain why it makes no sense, and show the same structured approach in tracking down the error. 

In summary, showing that “BCG attitude” is not some magic trick: stay humble, stay hungry, and try to have a good time. That’s about it. 

“Your client is the Health Ministry of a small developing country. They want to roll out a polio vaccination program for young kids. How should they go about it and what will be the cost?”

Opening 

The first thing to do is to repeat the main info in the prompt to the interviewer to make sure you got it right, and ask clarifying questions. If you don’t know what polio is or how old the kids receiving the vaccine against it are, it would be a good idea to ask your interviewer. Turns out polio is an infection caused by a virus that can lead to paralysis, and let’s assume we are targeting kids age 6 to 8. The location of the country does not particularly matter here.

Now is also the time to establish the client’s key success metrics: “What would success look like to the government of this country? Is there anything else they are worried about beyond costs?” Here, they simply care about reaching as many children as feasible in the country and want to estimate the costs. 

Structure

You’d now ask for a minute to lay down your thoughts so that you can build your structure. Notice that this case prompt is not your average profitability question so you can’t just use a framework you learned. 

Pro-tip! Take a moment to think about what you’d do before reading ahead, that’ll be infinitely more helpful to you. 

Here’s one proposal you could go with: 

• Logistics of the rollout program and the associated costs?
  • Target population
    • Program size
      • How many kids do we have to reach?
    • Access
      • What are the biggest locations across the country?
      • How do we make sure families are aware of our program?
      • How will kids enroll in our program? Do we go to them or do they get to us? (homes, hospitals, schools, etc.)
      • Any adjustment in rural vs urban areas? What’s the topography like?
  • Logistics of the programs
    • Staff
      • Medical: Doctor, medical personnel, etc.
      • Logistics: drivers, receptionist, etc. 
      • Do we need security guards?
    • Built infrastructure
      • Can we use any existing buildings?
      • If not, a pop-up tent, or is it worth building?
      • A medical bus?
    • Materials
      • Vaccines
      • Vaccine storage
      • PPE
    • Transportation
      • How many vehicles?
      • Any specialized storage needs? (frozen, etc.)
      • Any shipping costs? (for refills?)
  • Who will run this program? 
    • What are our client’s capabilities?
      • Have they done other vaccination programs in the past?
      • Do they have specialized medical staff who are public servants?
    • Who are the other actors in the area (that we could partner with)?
      • NGOs (such as Doctors without Borders)?
      • Private actors? (private clinic, etc.)
      • Neighboring countries with expertise?
    • Governance
      • Who is responsible? 
      • How is accountability measured?
• Financial considerations
  • How will this be funded?
    • Is there a budget? 
    • Do we need to apply for grants or international help?
    • If partnership, share costs?
  • What savings will come out of this program?
    • How much will we save in health expenditures down the line with fewer sick children? 
    • Can we also use this program to test/vaccinate for other usual suspects among children’s diseases?
• Other considerations
  • Do we have overall government buy-in?
    • What are our relations with the rest of the government? 
    • Do they see polio as a priority?
  • Public perception
    • How is the general population seeing the Health Ministry in that country? 
    • Could we leverage this program for a PR campaign?

This structure is pretty exhaustive. Don’t worry if you didn’t come up with every bullet point on your own.

In practice since you only have a couple of minutes at most to lay it out during your BCG case interview, you would not necessarily write these full questions on your piece of paper but a couple of keywords for each bucket and each sub-bucket.  

If you’d like to learn more about how to create a case structure, see our article on the Pyramid Principle.

Analysis 

Turns out the structure above is also pretty spot on. The first thing the interviewer would do after you lay it out is prompt you to brainstorm in-depth on the various ways to reach the kids, so if you’ve already alluded to it in your structure that gives you a headstart. 

On brainstorming questions, you’ll be rated on both your structure and your creativity. Make sure to always articulate the logic behind your ideas, using your past experience, analogies, or your general knowledge (“I remember when we got vaccinated for measles in our school…”). One way to go about it could be: 

• Getting to the kids (where are the kids?)
  • Schools
  • Hospitals
  • Homes
• Getting the kids to us (how can we get the parents to bring their kids?)
  • Hospitals
  • Pop-up locations by neighborhood
  • Have primary care providers refer them to us (is that feasible in this country?)

And the most pragmatic answer is of course to go where kids already are spending the most time, which is schools. Opt-in programs where recipients have to go somewhere end up having reliably lower reach, for various reasons from opportunity costs to the social stigma associated with going to locations like hospitals.

Once aligned with your interviewer on that, what would you ask next? (Remember the importance of drive?) 

Sample follow-on question: “Do we have any data on the school repartition in this country?”

You’d then be handed a first exhibit: a map detailing the number of schools in each area of the country and the average number of students per school. Let’s say that there are 5 schools in area 1, 3 in area 2, 2 in area 3, and 10 schools in area 4. Each school has on average 400 students in our target age range. There are thus 20 schools with 400 students per school on average. 

A great candidate will comment right away on the total number of students we are targeting, which is 8,000, and ask about any differences in the various areas that would require different logistics. There are none here.

At this point, knowing that we will be touring schools, the interviewer would ask you to brainstorm further all the precise cost items associated with that. This is already done a bit in our structure above (told you it was spot on) but you can give it a try for yourself. 

Once satisfied, they’ll give you a second exhibit, this time with the following data. In each area, there will be a team composed of: 

• 1x doctor ($50/day)
• 4x technicians ($40/day)
• 1x driver + vehicle ($110/day)
• Vaccines ($2/vaccine)

When seeing this, you might first want to ask about the slight ambiguity on the technician cost: it’s $40/day for all 4 of them, not for each. It’s up to you now to take the initiative to compute the cost of the program. 

Take a break and try now. What do you notice? 

You’re missing a very important piece of data: how many kids can we see per day? Only when asked about this would the interviewer share with you that it takes a technician 6 minutes to inoculate a vaccine to a kid. We’re almost there. Great, and how many hours can we work per day? You might ask if it’s ok to go with a standard assumption of 8 hours/day and your interviewer would let you know that in this case, it’s actually closer to 5 hours/day. Now we have everything we need! 

A great candidate will also notice right away that since we only have variable costs here, the total cost will be the same whether we consider one team per area or one team touring all areas, so we can group all the computations at once to avoid doing it area by area (of course touring the areas simultaneously will however shorten the program length).

Each technician can therefore see 10 kids per hour, hence you can vaccinate 40 kids per hour in total with 4 technicians in a school. With 5 hours of work a day, that’s 200 kids per day which means exactly 2 days per school for each team. 

Since there are 20 schools at $200 per day per school in staff cost and it takes 2 days per school, the total staff cost is $8,000 for 40 days of man-work. And of course, 20 schools times 400 students that’s 8,000 students which represent $16,000 in vaccine costs at $2/vaccine. The total cost of the program is $24,000 to tour all the schools once. 

When getting to any kind of number, always take a moment to sanity check whether they make sense and comment on them. Big picture, $24,000 feels like a low number for a national program, and it is; you can link that back to the overall low number of schools (only 20 for the whole country). Whether that’s a lot of money for the Health Ministry is however an open question, and you might also wonder whether all kids in the country are covered by these schools: were these only the public schools? What about the rate of absenteeism in this country?

You can also comment on the overall timeline: it will be driven by the biggest area which will take the longest to tour. It had 10 schools, hence the program can be over in 20 working days assuming that transportation and school schedules do not slow it down. 

Notice how doing the math methodically helped me realize that some data was missing? It also made the computations flow easily. Without a structured approach, it would have been easy to run around in circles or compute tons of useless intermediate results instead.

Conclusion

“The right hand of the Health Minister walks into the team room and asks you about your findings before she jumps on a call with her boss. What do you tell her?”

The final synthesis of your BCG case interview should lead with your recommendation to the client and details the key reasons supporting that recommendation. It then mentions any risks to consider which might impact the outcome and the next steps that you’d suggest to either cover these risks or double down on the analysis. There is no need to repeat everything you covered during the case: be succinct and stick to the key arguments.

What would you say? Give it a try before reading the end!

“We recommend rolling out the polio vaccination program for kids aged 6-8 by touring schools with one medical team in each area of the country. This program is reasonably low cost and would only represent $24,000 in funding and take only 4 to 5 weeks to reach all the schools in the country. 

One concern we’d like to address next is whether absenteeism is an issue that would prevent us from reaching kids, especially in rural areas. That might inform whether running this program once a year is enough.” 

Congrats, you made it through your first BCG case interview!

Still have questions?