Your client, an organic supermarket, wants to digitalize his business. How would you approach this case?

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. What Are Market Sizing Cases?If you're applying to top consulting firms like McKinsey, BCG, or Bain, you're unlikely to escape a market estimation case. Market sizing cases are considered "back-of-the-envelope" calculations because they can be done on the back of an envelope. Despite the name, it's not just about estimating market sizes; other estimations may also be asked for.For example, if you're discussing a British clothing retailer's growth strategy, you could calculate on an envelope how large the online clothing market is and what percentage of the market the retailer already penetrates. If you perform these calculations quickly, the conversation with the client stays fluid, leaving a good impression.You can receive the question about market size as a standalone case (although this is less common) or as part of a more comprehensive problem, such as market entry. The good news: There's no right or wrong answer when it comes to the question of market size. The interviewer is less concerned about the specific number you come up with for the market than the approach you took to arrive at that number. Why Are Market Sizing Cases Commonly Used in Consulting Interviews?Market Sizing Cases are used to test your quantitative and logical abilities. The interviewer wants to ascertain whether you work well with numbers and if you can make informed assumptions and deal with ambiguities. Questions about market size aren't just about the size of markets; they also involve other types of estimations, such as the number of golf balls in a jumbo jet. As you may have noticed, math is crucial in tackling these questions since you don't have a calculator to rely on. Most importantly, you need to be comfortable dealing with large numbers like millions and billions as well as percentages. More on that later. How Do You Best Approach Market Sizing Cases?Now that we understand the theory behind Market Sizing Cases and their relevance to your case interview, let's take a closer look at the process.Segmentation – The Key to Market Sizing CasesIf you've done some reading on case interviews before delving into market sizing questions, you might have come across areas where segmentation is necessary. Segmenting data is a crucial skill you must master as both a candidate in a case interview and in your later career as a consultant. Segmentation generally refers to dividing a larger whole into smaller parts or segments. The principle you need to understand to do this correctly is the MECE principle.MECE stands for "mutually exclusive, collectively exhaustive." Simply put, segmenting a group of data according to the MECE principle means forming subgroups that do not overlap but collectively cover the entirety of the data, meaning no data is missing. An example useful for market sizing questions is dividing a country's population into age groups (as different age groups often behave differently).Below is a breakdown into Group 1 in the age range 0 to 14, Group 2 in the age range 15 to 64, and Group 3 for everyone over 65: Note that none of the groups overlap, so no age is counted twice, but also no age is overlooked. Now that the population is correctly segmented, we can treat each group differently. If we had divided the population of the United Kingdom into the aforementioned groups, we could estimate clothing expenditures per person in these groups in online retail. Common sense suggests that expenditures per person in the 0-14 age group are lower than in the 15-64 age group. We can justify this estimation by noting that the majority of 0-14-year-olds do not purchase their clothing online. 

You've already learned the basics of case cracking, but now it's time to focus on how to take charge and steer the interview like a pro. Leading a case is all about showcasing your problem-solving skills, structuring your thoughts, and confidently guiding the discussion. Ready to master this crucial skill? Let's get into it! What's the Deal with Candidate-Led Interviews?First things first, what even is a candidate-led interview? In the consulting industry, particularly in top firms like BCG, Bain, and Roland Berger you’ll often face this type of interview. Essentially, you, the candidate, are in the driver's seat. Your job is to guide the interviewer through your thought process as you solve a business problem. It’s a bit like being the Sherlock Holmes of business – minus the deerstalker hat.Candidate-led case interviews are all about seeing if you've got that consulting mojo. The interviewers aren't just testing your problem-solving skills; they want to see how you think on your feet, structure a mess of information into a coherent plan, and communicate your ideas like a pro. They’re looking to see if you can break down tough problems, stay calm under pressure, and clearly explain your thinking. And, of course, they’re also sizing up whether you’d be a good fit with the team. So, show off your skills and be yourself! How Can You Demonstrate Case Leadership in Three Simple Steps?Don’t worry, taking on case leadership is not as complicated as it sounds. In fact, you can demonstrate case leadership in just three simple steps. Ready to impress your interviewers? Let’s break it down.