06 November 2022
An introduction
MECE is a principle familiar to those in the process of preparing for a case interview when joining the consulting industry. The term stands for Mutually Exclusive, Collectively Exhaustive and was first described by Barbara Minto who was employed at Mckinsey in the 1960s and 1970s. The concept can be broken down into its two constituent parts.
Firstly, the Mutually Exclusive part is derived from a statistical term that describes two or more events that cannot occur simultaneously and do not overlap. When attempting to solve complex problems such as in a case interview, it is paramount to break the problem into simple components to evaluate the root of the problem. Hence each item should fit into just one category to avoid duplication of ideas to elucidate a clear outcome to solve the problem. This is particularly key in the context of the case interview for simplicity, where only a limited timeframe is permitted. This is well exemplified when thinking about a coin toss. The outcome is either heads or tails, these outcomes cannot occur simultaneously.
Secondly, the Collectively Exhaustive part of this term refers to where all different parts account for the complete idea with no possibilities missing. It is key to create categories in problems where there is a finite number of general groups. For instance, when dividing up countries in the world, rather than saying ‘France, Japan, Canada’, it would be better to divide it by continents such as ‘within Europe, Asia, North America”. This ensures significant divisions aren’t forgotten.
Why is this important?
Not only does using a MECE format when answering case interview questions important to enable logical thinking and drive clarity of communication, but it also drives efficiency. This is more widely applicable within a consulting job additionally, where a consultant’s role is to meet the client’s needs using extreme clarity and rigor whilst minimizing risk.
Is being MECE enough?
Whilst structuring problems in the MECE format is vital, the structure must also be focused on the client’s needs, and on the specific case at hand. Furthermore, the points within your MECE structure must be organized within priority levels. Hence being ‘MECE’ is an essential principle to allow effective communication without repetition or leaving gaps in an argument to help crack cases in an interview or in general consulting work. It is also key to understand and be aware of other factors when solving a case as it simply isn’t enough to just be ‘MECE’.
