Be more MECE (mutually exclusive and collectively exhaustive)

Be more MECE (mutually exclusive and collectively exhaustive)

Feb 15, 2011

This is part 2 of our 4-part on MECE thinking — part 1, part 2, part 3, and part 4.We’ve talked about how thinking in a mutually exclusive and collective exhaustive way can help you actively drive structure in complex problems. In this post, let's look at how you can be more MECE in your thinking.

Consider focusing on being CEME, rather than being MECE

To consider all the possible solutions in an efficient manner to a problem requires being MECE. To do that, it may be simpler to first think about all possible solutions (eliminate gaps) and then to arrange them so that you only consider each one once (eliminate overlaps). In other words, you may make the process of searching for all possible answer CE then ME, rather than ME then CE.

The "collective exhaustive" part requires divergent thinking (also called creative thinking or innovative thinking). It will give you the big picture, as you're including everything. To produce it, you are asking “what else?” as in, “what else could be the source of my problem?” or “what else could be a potential solution for my problem?”The "mutually exclusive" part requires critical thinking and, ultimately, convergent thinking. Doing it, you are arranging answers and synthesizing. Being good at ME thinking, you'll have a clearly organized structure for your answers—root causes (for a why map) or potential solutions (for a how map)—in your question map so that you consider a possible answer no more than once. Organizing may work best when you already have some matter to arrange, as opposed to thinking out of thin air about possible categories and then populating them.In practice, developing a MECE structure usually requires iterating between these diverging and converging thinking patterns. Where you start, though, depends. It depends on you and how you're developing your strategic-thinking skills. It also depends on your problem: For some problems, a structure might already be available.

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Iterate back and forth between the ideas and the structure. Where you start (the idea or the structure) depends on your preferences—ome of us are more top down, others bottom up—and your circumstances: For some problems, it's easier to think of a structure than for others.Perhaps a helpful analogy is thinking about how to draw a complex subject, such as a human face. We each do it differently, but if you aren’t an expert, chances are that you’ll first go with a top-down approach: setting up the general shape of the face, placing the important features—the eyes, the nose, the mouth—and stepping back to ensure that it is consistent with your mental or physical model. Once everything seems to be more or less in place, you can focus on the details, such as adding the shading to the eyes that will create the desired impression. But there is no point starting with drawing the eyes and mouth in extensive detail just to step back and find out that they are in the wrong place. Even Picasso did it that way. Well, in all fairness, he probably could have started drawing his bull by drawing the eye and the horns—and they would have been beautifully placed—but, well, he is Picasso.

Usually you aren't really after being mutually exclusive

MECE thinking in business problem solving is a misnomer, firmly ingrained in the community courtesy of (it doesn’t matter because they all do it). The fact is, we are not really looking for mutual exclusiveness of solutions. Let me explain.

In the strict sense, two events are mutually exclusive if the occurrence of one precludes the occurrence of the other. The key word here is “precludes.” Usually, we aren’t interested in finding events that preclude others from occurring—otherwise, we would be preventing ourselves from following potentially viable options. What we are interested in is independent events: Ones that you can pursue individually.

Sometimes, you’ll be able to pursue several options at the same time. For instance, you might be able to boost profitability by acquiring more revenues from returning clients and also reducing your variable costs. If you're not limited by resources to pursue both means simultaneously, then these two options aren't mutually exclusive.

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A profitability question map shows all the possible ways in which we can increase our profitability.

Some other times, pursuing one solution will actually preclude you from pursuing another: If you’re traveling from New York City to London by plane, you can’t also do it by boat. But whether independent solutions are also mutually exclusive depends on the nature of the problem or the nature of the solution.

Even in a specific problem, you may have solutions that will prevent you from pursuing any other—for instance because they are time consuming—and solutions that will allow you to consider others. But this consideration comes later in your problem-solving process, when you are deciding on the solution(s) that you want to pursue.When organizing solutions, you should concentrate on making the branches of the map mutually exclusive; the actual content of the map, that is, the nodes, usually are independent. We'll talk more about that in part 3 of the series.


This is part 2 of our 4-part on MECE thinking — part 1, part 2, part 3, and part 4.Chevallier, A. (2016). Strategic Thinking in Complex Problem Solving. Oxford, UK, Oxford University Press, pp. 58–67.Davis, Ian, David Keeling, Paul Schreier and Ashley Williams. “The Mckinsey Approach to Problem Solving.” McKinsey Staff Paper, no. 66 (2007): 27.Eppler, Martin J. “Toward a Pragmatic Taxonomy of Knowledge Maps: Classification Principles, Sample Typologies, and Application Examples.” In Information Visualization, 2006. IV 2006. Tenth International Conference on, 195-204: IEEE, 2006.Gardner, Howard. Frames of mind: The theory of multiple intelligences. Basic books, 1985.Kazancioglu, Emre, Ken Platts and Pete Caldwell. “Visualization and Visual Modelling for Strategic Analysis and Problem-Solving.” In Information Visualisation, 2005. Proceedings. Ninth International Conference on, 61-69: IEEE, 2005.van Gelder, T. (2010). "What is MECE, and is it MECE?". Retrieved October 4, 2014, from credit: SatyaPrem/Pixabay.