Increasing Brain "Processing Speed" in Case Interviews


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. And to practice a lot of cases, should I choose to apply to other consulting firms.

I understand (and agree with) what was meant with this feedback. What frustrates me is that:

1) I (later on, after having thought about it) understood how I "should have" performed, what questions I "should have" asked, and what the implications were (perhaps feeling a bit like I know what to do, but it is not yet a habit).

2) I feel that I would have performed better if I had gone through this case interview process in a earlier stage (when I was using my brain more actively, finishing my two Master's degrees). Also, I felt a bit tired during the process, having not slept particularly well lately, as I recently became a lucky father.

Again, my question is how to get my "brainspeed" 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?

I am also considering purchasing your Look Over My Shoulder® program, as I am positive this would help with my habits.


My Reply:

Sounds like your talking lacks some precision and efficiency.  If you 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.

With respect to watching the clock, it's not so much you want to speed up.... 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 your wife or 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 really 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.

I definitely appreciate your comment about doing cases earlier in your career. Today, I am very quick on deriving insights from qualitative and quantitative information.

But my brain is so slow on math these days. As in what's $2 x 1 million units... umm, is that $2 million??

Seriously, these days I need a calculator half the time or have to do my math two or three times to make sure I did it right.. or ask someone to double check it for me.

One way to fix this problem is to force yourself to do a lot of math with big numbers. It's like a good high quality knife, it still needs to be re-sharpened to stay sharp.

So do some math every day... even if for only 15 minutes. Do it for two weeks, and that skill comes back pretty quick if you had it in the past but it's not there right now.

I covered the brain speed question in my answer to the earlier question, so let me add to that by saying it's worth practicing the math aspects so you're not using excessive brain power to do the math... and can focus on analyzing, implications, and conclusions.

So it's 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 "micro processor," to off-load processing work to the habitual level (as I indicated in my answer to the previous question), so that the entire "micro processor" (your brain) can be devoted to the aspects of the case that can not 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 onprocess things which could have been delegated to the habitual level.

So good luck and congratulations on the new addition to the family.  I'm going through that myself, and it is also one reason my brain is slow at this point. I will say one very practical tip, get enough sleep the night before. In my final round McKinsey LA, I was well rested, sharp and on fire.

In my final round McKinsey NY (transfer), I was very tired. I had the time zone change, which I did not factor in, and was really tired. Frankly I was bit off my game, but did well enough to squeeze by... and my performance in LA was probably why NY gave me the benefit of the doubt.

My point is sleep makes a 25% difference on performance and brain process speed. So in the grand scheme of things, it is easier to manage your sleep to get a 25% boost in performance than it is to improve your raw talent level by 25%.

You can access additional case interview prep materials the Members Only section of my website at .

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