When preparing for a case interview, especially under time constraints, working with an experienced coach can significantly enhance your chances of success.
💡 Pro Tip: PrepLounge offers access to over 800 (former) management consultants from top firms like McKinsey, BCG, and Bain, who are ready to help you perfect your interview technique.
What Are the Key Advantages of Practicing With a Coach?
Personalized Feedback
One of the primary benefits of working with a case coach is receiving tailored feedback. Unlike general preparation methods, a coach can pinpoint your specific weaknesses and provide actionable advice to improve. This personalized approach ensures that your preparation is efficient and targeted, addressing your unique needs and challenges.
Realistic Simulation
Practicing with a coach allows you to experience a realistic interview setting. Coaches who have conducted numerous case interviews can replicate the pressure and dynamics of a real interview, helping you become more comfortable and confident. This experience is invaluable, as it prepares you to handle the stress and spontaneity of actual interviews.
Insider Knowledge
Experienced coaches often come from prestigious consulting backgrounds themselves. Their insider knowledge about what top firms are looking for can give you a significant edge. They can share insights about the interview process, common pitfalls, and the specific attributes that firms value, ensuring that you are well-prepared to meet these expectations.
Structured Approach
A coach can help you develop a structured approach to solving case problems. This structured thinking is crucial in case interviews, where clear, logical, and well-organized answers are highly valued. Coaches can teach you frameworks and methodologies that streamline your problem-solving process, making your responses more coherent and compelling.
Time Efficiency
For candidates with limited preparation time, coaching is a highly efficient way to get ready. Coaches can quickly identify areas that need improvement, helping you focus your efforts where they are most needed. This targeted preparation can save you time and help you progress faster than you would on your own.
Confidence Boost
Confidence plays a crucial role in interview performance. Regular practice with a coach can boost your confidence by familiarizing you with the interview format and helping you refine your answers. Knowing that you have prepared thoroughly with expert guidance can significantly reduce anxiety and improve your overall performance.
How PrepLounge Optimally Supports You With a Wide Range of Coaching Options
🚀 Flexibility and Convenience
PrepLounge offers a variety of coaching options to fit your needs and preferences. You can choose from individual sessions, CV reviews, or comprehensive coaching packages that include multiple sessions or focus on specific topics. Additionally, there are programs available that combine a premium membership with coaching credits, providing a cost-effective way to access top-notch coaching services.
📅 Workshops and Online Events
PrepLounge also regularly hosts workshops and online events led by experienced coaches. These sessions cover a range of topics and provide opportunities for interactive learning and direct feedback. Participating in these events can further enhance your preparation and keep you updated on the latest trends and techniques in case interviews.
How to Find the Perfect Coach to Suit Your Needs
To find the perfect coach for your case interview preparation, you can proceed in three steps within the coach overview:
Filtering: Begin by filtering the coaches based on your most important criteria, such as price per coaching session, or employer.
Selection: Choose up to 10 coaches whose profiles, ratings, Q&A contributions, and PrepLounge awards you wish to explore further.
Contacting: Reach out to 2-3 coaches to address any potential questions or concerns about their coaching approach. Feel free to ask if they offer a free intro call.
What Makes a Good Coach?
Good coaches are characterized by the following features:
Customization: they tailor the coaching to your specific needs.
Good rapport: They make you feel comfortable and work well with them.
Transparency: They offer you full transparency about the coaching process on PrepLounge.
Final Thoughts on Working With a Coach
Practicing with a coach is a strategic investment in your case interview preparation. The personalized feedback, realistic simulation, insider knowledge, and confidence boost that coaches provide can make a significant difference in your performance. With the expert guidance available on PrepLounge, you can ensure that you are thoroughly prepared and ready to excel in your case interviews.
By leveraging the expertise of experienced case coaches and taking advantage of the diverse coaching options and events available on PrepLounge, you can maximize your preparation efficiency, build your confidence, and increase your chances of securing a position at a top consulting firm.
How much would you charge to clean all the windows in Seattle?
4 hrs
21.3k
51
Best answer by
Antonello
It is one of the most popular Fermi questions and you could face it during the 1st round, when math and problem-solving skills are usually tested deeply. I will propose a quick solution, in order to give later some detailed considerations.
Let's estimate the number of windows in Seattle.
No. of residents in Seattle: you do not have to know that Seattle has almost 750k residents, but a good candidate should infer that it is a big city in the US and that can be assumed it has 1M residents.
No. of windows per residents: you are actually interested in the number of facades to clean; a small window has 2 facades, the inner one and the external one, while bigger windows have 4 or more facades. Let's assume that an average residence in Seattle has 2 people and 40 window facades. So we have 20 residential facades per inhabitant. Let's assume to have other 20 commercial window facades per resident, including e.g. bars, offices, stores.
-> 1M residents x 40 window facades, we have a total of 40M facades to clean.
Now let's evaluate the charge per facade.
Facades per hour: the time requested for a wide window of a store will be much higher than the service window of a little house. Let's assume an expert cleaner will take 1 min for a medium-sized window, i.e. 60 facades per hour.
Charge per hour: let's assume an hourly rate of $10. We should also consider the cost for infrastructures, tools, products, and insurance: let's estimate other $5 per hour.
-> in an hour: $15 / 60 facade, that gives 25 cents per window facade.
--> Therefore to clean all the windows of Seattle you could charge $10M ($0,25 x 40M).
Remember: in consulting nobody knows the number of windows in Seattle and maybe neither in window-cleaning companies :) What will be valued is not the accuracy of this type of numbers, but the reasoning you make behind them and your common sense (you should always wonder if numbers you estimate have sense or not). In addition, when you complete an estimation (e.g. the no. of residents in Seattle) you can ask the interviewer whether you can proceed with that number or she has something more accurate.
The solution proposed will be considered great and will allows you to pass the round. But in order to really crack it and impress the interviewer, you should be more curious, proactive and come up with creative considerations, potentially based on personal experience. Some examples:
When you calculate the no. of windows in town you can make some comparisons with your city, e.g.: "in Manhattan, I feel lucky with just one window at home, but I know that Seattle is more residential, houses are bigger and they usually have beautiful views on surrounding gardens and parks. Therefore let's assume an average house has 4 little windows (2 facades each), 4 medium (4 facades each) and 2 big (8 facades each)."
Think out of the box: ask the interviewer if you should also consider the car windows.
When you evaluate the cleaning speed you can say, with a bit of healthy self-irony: "A medium-sized facade take me at least 3-4 minutes to clean it. But I know to be a disaster :) I assume an expert cleaner with professional tools can handle it and move to the next one in 1 minute."
In the end, to consider other risks not covered in the discussion, you could also introduce a safety factor, e.g. "the time evaluated do not consider the time to put up and put down the infrastructure and the time needed to wait for residents to free up windows. For these and other possible risks we should consider an increase of 10% of the estimate."
BCG "Under Review", how long is too long, and what should I do next?
8 hrs
< 100
3
Best answer by
Franco
Hi, 8–9 weeks isn’t the norm, but it doesn’t signal a rejection either. If they had decided to pass, you would’ve heard by now. More likely, something internal (capacity, timing, office needs) or external slowed things down and your application is still being processed. Best move now: send a short, gentle email to recruiting asking for an update. Hope it helps Best, Franco
Hi, Referrals mainly help at the resume screening stage;they can increase the chances that your CV gets reviewed more carefully or passed through the initial filter. However, they don’t give you any major advantage during the interviews; from that point on, it’s all about your performance. The ideal scenario is to have a direct contact in your target office who can refer you. If you don’t have one, you can still “engineer” it by reaching out to people (e.g., alumni, LinkedIn, events) and building a connection. If that goes well, you can ask for an internal referral or recommendation, but this needs to be done well in advance of your application, not last minute. Hope this helps. If you want further information feel free to DM me Best, Franco
What would you ask me if you were the interviewer?
11 hrs
6.3k
44
Best answer by
Gero
#1 There is a better response Great ideas in this thread. However, an exceptional candidate would answer the question in a unique way that cannot be prepared in advance - he/she would use some piece of information about the interviewer to show they can do relationship-building by coming up with interesting and engaging questions that are relevant to the interviewer. #2 What great candidates do That information can come from the interviewer bio. Even better would be from the previous interview discussion directly. The best candidates I experienced in the fit part were able to co-create an interesting dialogue by managing (storing and using it at the right time) the chunks of personal information I shared, showing genuine interest in me and not only their own success (even if just as a tactic). #3 How it may look like One example that I was actually asked (and liked): “Given your commitment to coaching colleagues at BCG (that I had shared as part of my short intro), how would you say is coaching different from your consulting work?”
Mckinsey Quantum Black SWE Virtual Problem Solving Case + Personal Experience Interview
12 hrs
< 100
3
Best answer by
Cristian
Congrats! Regarding your last question, on whether the case will be QB-specific or generic, do ask the recruiter directly. They're best positioned to tell you. On the personal fit, read the guide that McKinsey sent you and you might also want to consider this targeted PEI course I've built which lots of candidates are finding useful: • • Video Course: Master the McKinsey PEI Best, Cristian
Question: "Is there something we haven't asked you that we should?"
12 hrs
< 100
5
Best answer by
Franco
Hi, I think that would have been your chance to highlight a strength and position yourself clearly in front of the interviewer. Saying “no” won’t kill your chances if the rest went well, but it’s not the most elegant answer; you’re leaving value on the table. A simple pivot works: “Actually yes, we didn’t touch on [X], which is one of my key strengths. In my last experience, I…” Good luck, Franco
McKinsey Data science I TEI+PEI and pair programming
13 hrs
1.2k
3
Best answer by
Kevin
This is a great place to be, and you've hit on the central challenge of specialist recruiting at MBB: the expectation for deep technical rigor combined with the standard behavioral screening. Don't worry about only having internships and hackathons; that is exactly the type of experience they anticipate for entry-level specialist roles. The key is how you frame those experiences. For the TEI (Technical Experience Interview), McKinsey isn't looking for proof you’ve managed a $100M project; they are looking for rigor in your decision-making. You must treat every past project, even a hackathon, as a full-cycle business problem. Use the STAR method, but focus the "Result" less on the final accuracy score and more on the trade-offs you made: Why did you choose that specific model over another? What critical data leakage issue did you solve? How did you ensure the solution delivered value to the user/client, not just good metrics? This interview is designed to ensure you think like an applied Data Scientist, not just a coder. The PEI (Personal Experience Interview) remains the gatekeeper, just as it is for the generalist role. Your technical competence gets you the interview, but your ability to exhibit leadership, entrepreneurial drive, and personal impact determines whether you get the offer. You must develop 3-4 deep, polished stories (drawing from those internships or even academic group projects) that squarely hit those three dimensions. Be ruthless in sticking to the structure and focusing on your specific actions and impact. Finally, the Pair Programming session is not a competitive coding exam. The primary goal is to assess your collaboration style and ability to handle ambiguity under pressure. You must communicate every step of your thought process—literally narrate your plan, the edge cases you're worried about, and why you are choosing one Python library over another. Talk out loud constantly. If you get stuck, explain where you are stuck and propose a pivot to the interviewer. Showing strong, structured thinking and collaborative problem-solving is far more valuable than optimizing the last two lines of code. Hope this helps you focus your prep! All the best.
I get this question a lot, and I think there’s a common misunderstanding here. A hypothesis is not a guess. It should be based on some evidence or logic, not something you “throw in” at the start. So for your two scenarios: I wouldn’t do either. Stating a hypothesis right after reading the prompt or right after your structure is, in most cases, just guessing; and that doesn’t add value. At the beginning of a case, your job is to: clarify the problem build a solid structure Not to predict the answer without data. The only exception is if you have very specific prior experience in that exact industry; then you can say something like: “In similar situations I’ve seen X being the main driver, so I’ll keep that in mind as we analyze.” But even that should be light, not a strong claim. The right moment to use hypotheses is during the analysis. For example, after looking at a chart or doing a calculation, you can say: “Based on what we’re seeing, I’d hypothesize that the issue is coming from X rather than Y.” That’s much stronger because it’s grounded in evidence. For a profitability case, a good hypothesis would be something like: “Given revenues seem stable and costs have increased, I’d focus on cost drivers as the likely root cause.” Bottom line: don’t force a hypothesis at the start; build it as you learn more. Hope this helps, Franco
Best free resources (YouTube/playlist) to learn consulting end-to-end?
18 hrs
< 100
5
Best answer by
Tommaso
Hey, thanks for your question. I have to say, it's one I get a lot, especially from my American students.The reality, in my opinion, is that the reason PrepLounge and other platforms are so successful is exactly because studying for MBB case interviews is very different from everything else. It's a highly active type of studying where you actually have to try things out. You need to practice structuring your thoughts in a MECE way and communicating them clearly. You have to practice doing market sizing (crunching the numbers and stating the results out loud). And you need to be able to manage the communication, because a case isn't something you solve on your own; you do it by picking up on hints and properly understanding the information coming from the interviewer.For this reason, I think case interview prep is very different from other subjects you might just study on YouTube. It's not like a history lesson where you can just take notes on what is being said, memorize it, and repeat it. It's an approach based entirely on planning, testing yourself, failing, and learning through that process. So, I honestly don't recommend using YouTube as your primary resource.I want to be very transparent here: I'm not saying this because I think coaching is strictly necessary :) It really depends on the individual. For many people, simply practicing with other peers who are also prepping is enough. But YouTube alone just won't cut it.However, if you do want to do some passive listening (and keep it as an important part of the preparation), I highly recommend looking up the audio or video content by Victor Cheng. He is an American coach who shares recordings of actual cases he's run with his clients. There, you can listen to how a case is handled, judge for yourself whether the candidate did a good or bad job, and then hear Victor's feedback.That being said, even in that scenario, I think the best way to utilize those recordings is to try and actively solve the case alongside Victor and his coachee :) Hope this helps! Tom
Questions about market size are frequently asked in case interviews in consulting because they require a blend of logic, mathematics, and common sense. They can be asked as standalone questions or as part of a larger case. Applicants who are familiar with market sizing questions can really perform here.
Market entry cases are one of the key issues in the consulting industry and present consultants and firms with unique challenges and opportunities. These cases require deep analysis and strategic planning to successfully enter new markets.
Brainteasers are a type of problem that focuses on a single issue rather than complex business cases. They require out-of-the-box thinking, logic or math skills and can take the form of riddles, word problems or visual puzzles. These tasks are designed to test your problem-solving skills, analytical thinking and ability to remain calm under pressure.Typical problems cover everyday life's topics and might even include unrealistic assumptions. All necessary information is usually included in the question so that further assumptions are not necessary. This article explains in more detail why brainteasers are useful in case interview preparation and how to solve them.