In today’s article we are going to talk about a perennial problem our clients across the world are facing – brainstorming aka building case structures. They are actually the same thing. And I have also seen applicants and consultants struggling with brainstorming when I was still a partner in management consulting.

In fact, I remember struggling with brainstorming myself, before I discovered an effective, beautiful and simple brainstorming technique which we will share with you in this article and which our clients attribute as an important contributor to their success in joining top consulting firms and in succeeding as management consultants.

If you master this brainstorming technique, you will set yourself apart not just during consulting interviews but for the rest of your consulting career and beyond, since this brainstorming technique teaches you how to analyze any problem in a structured, focused and logical way.

For clarity, the brainstorming part of the analyses will not take you through the entire problem solving process all the way to the solution. But it will help you progress through the initial part of the problem solving process in a structured and logical way, while guiding you to stay on the right track towards the right solution.

In fact, this brainstorming technique is designed in a way so that if you do the steps correctly, you will be guided to stay on the right track in your analyses. Hence, you will have higher chances of arriving at the right answer.

What is brainstorming within the context of management consulting

When we talk about brainstorming within the context of management consulting and the consulting case interview process, we are not referring to the kind of brainstorming that Alex Osborn (the “O” of legendary ad agency B.B.D.O.) invented in the 1930s and popularized in his 1953 book “Applied Imagination“.

The kind of brainstorming where a group of people throw out ideas in a meeting, or in Osborn’s words “using the brain to storm a creative problem”, and do so with the absence of criticism or negative feedback. The kind of brainstorming that, according to Osborn, was central to B.B.D.O.’s success.

That does not work in management consulting.

When we talk about brainstorming within the context of case interviews and management consulting in general, we are talking about a very structured, methodical, logical process of identifying drivers of the issue, which ultimately can be showcased as a decision tree.

When brainstorming is used during the case interview, it is usually an activity that the candidate goes through alone, with potential help from the interviewer.

In case of brainstorming within the context of a real strategy study, brainstorming can be done by an individual or a few members of the team. However, it is still a very structured and methodical process which has little resemblance to Osborn’s brainstorming technique.

Where brainstorming fits in a strategy study

In our strategy training program we teach, in depth, how to do brainstorming and where it fits in a strategy study. But at a very high level, the strategy engagement structure can be simplified into 6 basic steps, keeping in mind that it is an iterative process. And the brainstorming fits within the step 2 of this process, as shown in the diagram below.

As you can see, brainstorming allows you to generate the appropriate case structure.

brainstorming techniques management consulting strategy

The team comes up with the key issue. The key issue is then broken down into sub-drivers that drive the primary issue. This is, of course, done in a logical and structured way. This part of the strategy study is often called “structure the problem” or brainstorming.

The decision tree has to be mutually exclusive and collectively exhaustive (MECE). An example of a decision tree is shown below.

brainstorming decision tree

Once the decision tree is completed, branches of the decision tree are prioritized and hypotheses are developed.

Once the hypotheses are developed the team comes up with analyses required to test the hypotheses, builds the workplan, conducts analyses, synthesizes findings and presents the final recommendation to the client.

Where brainstorming fits in a case interview process

You will likely need to do brainstorming during each round of the consulting case interview process, including the most important final round with partners.

If you have been in a final round of the consulting case interview process, you know that you will face several principals or partners. And the interview could be anything from a very detailed case with a lot of graphs to just a discussion.

But no matter what will be the structure of your final round, at some point you will most likely need to do brainstorming. Armed with this brainstorming technique, this will be your chance to showcase what an analytical, structured and focused thinker you are.

I was a big fan of using the “discussion” format during the final round of case interviews. I preferred to avoid giving candidates, what I called, traditional cases. I found it more valuable to talk to them about general topics and see how they analyze problems.

As part of such general conversations, candidates inevitably had to do brainstorming because I needed to see how they think. And most of the candidates failed to showcase their ability to brainstorm in a structured and focused way.

An effective 2-step brainstorming technique

As I pointed out earlier, most candidates and consultants struggle with brainstorming. Brainstorming is incredibly difficult if you do not have a process to follow. Below we are sharing with you a two-step brainstorming technique that proved to be incredibly effective and should help you brainstorm better.

brainstorming technique consulting

Step 1 of the brainstorming technique – define the issue

When you are meant to brainstorm something, the first thing you need to do is to understand the definition of what you are brainstorming. Once you come up with the definition of what you are brainstorming, make sure you confirm your definition.

If you are brainstorming during a consulting case interview, confirm your definition with the interviewer. If you are brainstorming as part of a strategy engagement, confirm your definition with your colleagues.

The majority of candidates and consultants, unaware of this step, jump right into brainstorming without carefully considering the definition of the issue. They usually have a vague idea of what the definition is, but not much thought goes into defining the issue.

An example of incorrectly defining the issue

One of the classic cases we do is, “Explain to me how BMW could improve productivity in its facilities”.

When I introduce this case, candidates usually go ahead with the brainstorming, not giving any particular thought to the definition and, from the top of the mind, assume that productivity must be a number of cars BMW produces in a year or over some fixed time period. What is worse, they fail to run this definition by me and just move ahead with the brainstorming exercise.

Once it is clear to me that the definition is wrong, I usually ask candidates how they defined productivity. After they share with me their incorrect definition, I point out, “Are you sure this is the definition of productivity?”. And they usually say, “Yes, I am sure”.

This may surprise many people but there is only one definition of productivity, despite what you may have seen on graphs somewhere. Those graphs are just spinning the definition of productivity to make the analyses depicted in those graphs support the author’s argument.

The only definition of productivity anywhere in the world is the total value of outputs divided by the total input cost of producing those outputs, adjusted for the time value of money. There is no other definition.

The correct definition of the issue increases your chances to stay on the right track

So what you will find is that candidates start brainstorming immediately but they haven’t carefully considered the definition of productivity and they have not confirmed that their assumed definition is in fact correct.

Yet, if you define productivity first, your brainstorming becomes a lot easier because you can understand what is driving this definition. And knowing what are the drivers of the definition significantly increases your chances to stay on the right track as you continue your analyses.

So the first thing you should do is define what you are brainstorming and you would be surprised how many candidates and management consultants fail to do this.

Step 2 of the brainstorming technique – build a decision tree 

Once you are happy with the definition of the key question, in our example the definition of productivity, the next step is to build a decision tree (on paper or in your head). If you cannot write down or visualize the decision tree, you are not brainstorming.

The key question is then split into sub-questions or drivers in a logical and methodical way. Those sub-questions are further split into drivers of sub-questions.

Continue with this analyses until you can prioritize the key drivers and move on to develop hypotheses. Your brainstorming analyses will usually not go further than a 4th level of a decision tree.

Learn to do brainstorming in your head

With most brainstorming you will have to do it live in your head, especially if you are brainstorming during a case interview. It is unlikely that interviewer is going to give you a chance to write it down.

Moreover, if you request to write your brainstorming down, it shows that you cannot think logically without writing things down, which the interviewer will see as a red flag. In fact, interviewers specifically ask to do brainstorming off the top of the head to see how candidates think.

Think of drivers and use the word drivers

As you develop a decision tree, always think of drivers and use the word “DRIVERS”. If you don’t use the word drivers, you will say something like, “Well, how can BMW increase their value? They could maybe launch new cars. Maybe they can produce more cars”.

The thing is, when you don’t use the word drivers, you are simply throwing out ideas. And when you are throwing out ideas, you don’t know if it’s linked to the definition. Hence, you don’t know if you are on the right path with your analyses.

So use the word drivers so that you can ensure that whatever you throw out is linked to the issue that you are brainstorming. If you don’t do it, you are shooting yourself in the foot.

And it is not easy to think in terms of drivers. Most candidates struggle with this. Even if I tell them, “Use drivers”, two seconds later they will be throwing out ideas.

Once you break down the first level of your decision tree, I want you to do the next level using the same brainstorming technique. A common mistake people do, they will use drivers correctly for the first level of the decision tree, but for the second level they just start throwing out ideas.

The origin of confusion w.r.t. brainstorming in management consulting

The confusion around what brainstorming analyses refer to within the context of management consulting is caused by the fact that when candidates or consultants hear the word brainstorming, unless they are equipped with an effective brainstorming technique designed for consulting type of brainstorming, they tend to confuse consulting brainstorming with Osborn’s brainstorming technique.

Osborn’s brainstorming technique is right to left thinking. It’s where you throw out ideas and then you see whether it fits the problem on the left hand side.

Brainstorming within the context of management consulting, using the decision trees based brainstorming technique we shared with you in this article, is left to right thinking. You start with your question and you build your decision tree going from the left hand side of your sheet of paper to the right hand side of your sheet of paper.

If you don’t like the 2-step approach, think of it as 3 rules for brainstorming

When you are brainstorming, you must always think of these 2 steps. If you prefer rules to steps, think of it as 3 rules approach to brainstorming.

The 3 rules for brainstorming

1) Define the issue: Always ask “what is the definition?”. If you get the definition wrong, then you will be brainstorming incorrectly. Also, make sure you confirm the definition.

2) Brainstorm via building a decision tree: Make sure you are building a decision tree (in your head or on paper). If you cannot visualize a decision tree, you are not brainstorming. Because if you cannot visualize the decision tree, you don’t have structure in your thoughts.

3) Think and speak of DRIVERS: As you develop the decision tree, always use the concept of drivers and use the “DRIVERS” language. And obviously, you have to prioritize the drivers as well.

This simple brainstorming technique works for everyone

In my opinion, there is no better way to do brainstorming. This brainstorming technique works very well. We used it with all our candidates and I used this brainstorming technique when I was a management consultant all the way up to when I made a partner. We still use it on our studies. It is a simple technique and it works for everyone. Just remember these 2 steps or 3 rules and you will be fine.

As always, post your comments and I will be more than happy to respond to them.

QUESTION(S) OF THE DAY: How easy is it to abandon existing brainstorming techniques and use this approach? Please let us know in the comments.

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14 responses to Brainstorming technique used by consulting partners

  1. Thanks Tyler. Good points.


  2. I have used the well-known Alex Osborn’s approach in group facilitation sessions. Often these are more about getting everyone on-board with a change, or working across divisions. This can be crucial for the work I do where you report to a division head rather than the CEO.

    These sessions were most effective when spent the first hour and a half as a group defining the problem statement. After that we would brainstorm “solutions” and then group them into MECE categories. We would then identify resources required for each solution, and end by identifying the most viable options for detailed assessments.

    From my research, this is similar to how organizations like IDEO, Samsung, Apple have improved on the initial method. For many internal teams, they are not reporting to the CEO so they need to influence change rather than having direct support for it, and this may be why they use these variations.


  3. Yes, business judgement is critical to make this work.

  4. I think the technique is easy to switch, however, what is harder is the foundation. When I first start switching from the Osborn method to the FC method, I understood the technique, but struggled figuring out the drivers themselves or if I did figure out the drivers, I wasn’t sure if it was MECE, more CE than ME. Overtime, as my business judgement improved through reading the articles on “What FC is reading?”, so did my brainstorming,

  5. Hi Mat,

    That will be confusing to those in consulting who call this brainstorming. I suppose applicants will just have to use the language and terminology of consulting!


  6. Maybe “brainsteering” would be a better name for this process, as Kevin Coyne suggested in his article in HBR?


  7. Thanks Brian.

    You are indeed correct. Consulting uses a different definition from all other sectors.

    Thanks for pointing that out.


  8. This is one instance where terminology serves to complicate things rather than simplify them. I think the consulting world, in this case, could help in alleviating the confusion. Most of us, myself included, think of brainstorming in the creative sense. Coming up with solutions to a problem. Consultants, as I now know from some of Michael’s videos, use this to define a problem. This is very different.
    I also do not think people would have a hard time picking up structured brainstorming as long as they know what it is . The Six Sigma world uses this all the time in the define phase of a project. Usually you come up with an operational definition of an issue and then try to determine the “Critical to Quality ” or “Critical to X” drivers. This is done to narrow down a fuzzy issue into something measurable. Brainstorming in the traditional sense is used later to arrive at solutions.

  9. Hi Femi,

    I like this. You are right. Different segments of users will find this to be different.


  10. Hi Scott,

    My advice only refers to management consulting. It does not refer to other sectors, thought I know this approach works well since so any consultants thrive in other industries.

    Not having worked at IDEO or Apple, I cannot comment on what they do. Though you make the assumption they would not improve if they adopted the consulting approach. How do we know they would not improve their product development processes adopting the consulting approach? That is a big assumption. I am just putting that out there since it is possibility.

    There is one major difference between McKinsey/BCG and IDEO/Apple. We never ever design products for consumers. They do. I suspect that is the reason they use a different approach.

    I believe I covered this difference in a separate podcast.

    Product design is a very different process where there is no clear objective function. Consumers have varying needs for a product. Without a clear objective function the consulting brainstorming approach cannot work. I suspect that is the main reason they cannot use it. If you have a clear objective function, why do you need to go so broad like the Osborn approach?


  11. Hi Michael,

    I agree that this structured method of brainstorming is a great way to identify the key issues and problems and is the predominant way of thinking in management consulting. However, it seems like Osborn’s method could be used to great effect in conjunction with the more structured approach to identify more creative solutions.

    There must certainly a good reason that many major design firms (IDEO, etc.) and corporations producing consumer products (Apple, Samsung, etc.) use a variant of Osborn’s method. Most academic design programs also teach an, at least initially, very open and unstructured brainstorming methodology. Could you elaborate on why you believe this type of brainstorming does not translate as well to consulting? Do you think there is no place for it at all?

  12. In terms of how easy it is to abandon existing brainstorming techniques for this approach, I think it will be user situation-specific. For convenience, we might be able to fit all users into two buckets. Those with whom this approach immediately resonates (for whatever reason) and those who have to justify the switch to themselves.

    For the first population, my guess is that, the switch will be less cumbersome because they are not likely to have allowed existing approaches to take root. This is a complex thing to achieve in the mind but it is possible. You can do something very well without believing in it. Thus, for such persons, it might be easy to “move on.”

    For the second population, it could be challenging. The real issue may be anywhere from the inability to immediately see the merit in the simplicity of this approach to the tendency to assume getting a great job must be a result of complex interactions! Whatever the case, I think it will serve such persons well if they considered a number of issues. First, how do we naturally approach problems as human beings? How did we solve problems while growing up? In my experience, we tended to interact with vague concepts by simplifying them or by “bringing them closer home,” using examples or descriptions that we were already familiar with and I think this relates to the brilliance of this approach. The practice that reaches into a toolbox and then emerges with a case framework or formula is not representative of anything we did while growing up. It is probably representative of what we did in the math/physics/chemistry class where we learnt pre-determined formulas and then applied them to specific questions. But that may not work well with cases. Why? Those math questions were representative of controlled environments where dynamism was either held constant or considered negligible. As such we cannot relocate the formula method without consequences. We need to “reason through.”

    I hope this answers the question by a fraction of an inch.


  13. Hi Femi,

    I am glad you find it useful. You are welcome to use the material.


  14. Hi Michael,

    Thanks for supporting these evergreen podcasts (Brainstorming With Definitions & Fatal Brainstorming Mistake Made By All) with a text file. I hope you do not mind that I copied the text and fitted it into a M Word file for ease of personal consumption. I have preserved all FC emblems on the material, particularly the exhibits.

    The first time I listened to these podcasts, it was such a great relief! I don’t know if you have ever been in a situation where, even though you were searching for something frantically, you could not really describe what you were looking for. You have an idea of it and you believe it surely must exist. This was my experience.

    I had been inundated by the many frameworks out there but always had this intuition that, the approach of “fitting” frameworks to cases could not be ideal. It did not agree with the way we were trained in medical school (to solve problems). There was a lot of “reasoning from first principles” and you would literally hear professors “scream” it. Thus, I was searching for “something” other than what was out there; I guess I wanted “something” that I could layer on what I was trained to do.

    Such was the indescribable feeling I had when I listened to the first podcast on brainstorming. I took notes twice to be sure I missed nothing and then combined the two notes in my case study book. I have listened to the podcasts a number of times since then, just to fully internalize the learning.

    I have not perfected the art of brainstorming and neither have I perfected the act; I am still many miles away from shore, but I am happy to continue to travel with this strategic resource. And, since I may end up as a venture capitalist someday, I put my money on it!

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