This student sent me an email recently asking my advice on how they could practice and improve their performance in the problem-solving part of a case interview. Below is the students question to me as well as my response and advice on how to best practice this skill.

Reader’s Email

First of all, many thanks for all your information and encouraging words on case interview preparation .

Secondly, I would like your advice on how to get my “brainspeed” or “processing speed” up (the problem-solving part of the case interview).

Here is the deal, I got a first-round interview at McKinsey, but did not get through to the second round. I got the feedback that I do have the necessary skills to be a great management consultant, but it just took me too long to “see” the implications in the cases.

So, my question is how do I get my “brain speed” or “processing speed” up in order to become more alert to see the implications quicker. Can you recommend particular “brain exercises” relevant for the problem-solving part of the case interview and consulting in general?

My Response

Sounds like your case interview performance lacks some precision and efficiency.  My first recommendation is listen to the 2nd or 3rd case in Look Over My Shoulder®, the last example….  the whole interview was done in 22 minutes.  I specifically point this out, so you may want to search the transcript to find the example I’m referring to.

Study the words the interviewer said and compare that to some of the lower quality interviews.  There is a very precise quality to it.

You will notice that the interview does not feel rushed… the candidate is not speaking fast. He’s just asking very specific questions, looking for a very specific piece of information (including looking for qualitative information which = listening more) …. and notice after he asks for a specific piece of information, he explains the significance of what he just learned – concisely.

It’s not so much that you want to speed up…the interview, you want to eliminate the waste in what you ask.  You might want to try the following method of case interview practice, if you have the time.  Have someone give you a case…record it, pay someone online to transcribe it… and see which things you said were unnecessary… so sort of re-write the transcript to cut out waste… and notice what you cut out.

My best guess is you are wasting words, exploring things that are not necessary to explore… doing a thorough job of analysis which is wrong.You should do the minimally necessary analysis to answer the question, and not one bit more.

Let me add it’s worth practicing the math aspects of a case interview as well this way you’re not using excessive brain power to do the math… and can focus on analyzing, implications, and conclusions.

It’s much easier to train and improve math speed (make up math problems involving large numbers one night, and practice them the next), it’s much harder to practice “brain speed” (though improving math performance is correlated).

My strategy has been rather than try to speed up the “microprocessor,” to off-load processing work to the habitual level so that the entire “microprocessor” (your brain) can be devoted to the aspects of the case that cannot be made habitual… the aspects of the case that are unique to that particular case.

This reminds me of my own case interview skill level evolution early in my interviewing process. I was very good at frameworks — memorizing them, memorizing specific question-asking sequences (e.g., you get a number, break down to its components, ask for historical data to see the trend line, compare to the rest of the industry… auto-pilot stuff which is on my case interview frameworks handout).

By the end, I pretty much forgot all the frameworks. I never thought about them for one second. I used them flexibly and interchangeably on the fly.

When one of the frameworks did not fit, I tossed it out the window, created a custom issue tree on the fly, all without thinking about it much.  It was very natural, like breathing.

Now it took a ridiculous amount of practice to get there, but by that point I could devote all the brain processing power I had (essentially talent) to analyzing the issues of the case, rather than wasting those brain cycles on process things which could have been delegated to the habitual level.