How to be 80/20 without sacrificing comprehensiveness during a case interview?

Q: How to be 80/20 without sacrificing comprehensiveness during a case interview?

A very important question. First I must say that I strongly agree with the points of answer provided by the experts prior to me. Additionally, in case it helps, I would like to suggest one practical rule that I encourage my mentees to use and that usually works for that matter (although it is far having universal applicability): after you do some case interviews, you start realizing how deeply you know a subject and how long it takes you to think of each structured topic after the interviewer’s question. During the period of laying down your structure and thinking of the pillars of your analysis, you know that you can come up with a few points very quickly and then, as you progress, the time needed for you to come up with new topics starts to increase significantly. At that moment, you should ask yourself: “it is worthier spending extra 30 seconds to have a potential new topic or immediately to go back to the interviewer stating that I have not been 100% exhaustive but for the sake of time I focused on the ones you think are the most important”? When that moment happens and you state this to the interviewer, you are letting him/her know 2 things: that you can come up with new ideas if needed, and that you can use the 80/20 rule to the problem itself and to the use of the interview time. That way, you avoid spending 3+ minutes laying a very complex structure during which there is no exchange between you and the interviewer.

A final suggestion is to try to anticipate how much you should prioritize completeness over speed depending on which firm you are applying to. You might find that different firms might have slightly different preferences regarding this tradeoff.

I hope it helps and don’t hesitate reaching out if you have any questions.

Best of luck!

It would be useful if we were discussing specifically on a case prompt, but on a general level, one practical way of applying 80/20 on the framework discussion is to align with the interviewer where you dive deeper. 

So let's say that based on that prompt, you come up with 4 areas that you'd like to investigate, each of them with subpoints. 

But based on what you know about the client and their ambition, there are 2 areas in particular that you believe you should start with. 

You can communicate this to the interviewer + your motivation, align with them that you're going to proceed this way, and then go deeper there. 

This way you're drilling in a more 80/20 way while also making it more conversational (and closer to what a client interaction would go like). 

You might also find some useful insights on structuring here:

Expert Guide: Mastering Structuring & Brainstorming

Best,
Cristian 

Most likely this is more about communication than about comprehensiveness. I find some candidates to feel the need to justify every assumption / topic with 3 different drivers / reasons, and also to provide very long explanations (usually repeating themselves a few times). 

The answer is practicing “economy of speech”, i.e., to speak in “short bullet point format” (i.e., say what you mean in just a few words), to organize you thoughts ("I have three reasons: 1 - X; 2 - Y; 3- Z") , and to listen to yourself and stop when you are going to repeat over again.

Your counterpart, the interviewer, is smart, and gets things really quickly. While you have to say verbally what you think you don't have to over-explain.

Hi there,

Without having seen your communication and answers, I would guess that there could be two issues, a. content that boils the ocean, i.e. too broad, or b. communication that is not concise enough.

Content:

The goal of the framework is to give you the analytical lens to investigate the situation and understand the problem and/or answer the client's question. 

Your task is to frame the problem exactly in the right way, i.e. cover it fully (this is something you should aim for and there is no harm in doing so - most candidates fail here) but at the same time not include elements that have no or very little relevance to the question at hand.

I could imagine that some of the top-level buckets are not that relevant and do not yield any important insights for the analysis.

Another way to become lengthy is to include too much depth (again something that is rarely seen - most candidate's frameworks are too shallow) by branching out into 3-4 sub-levels for each category. While for McKinsey this is something that is desired due to the interviewer-led format, for other firms you should go less deep and only drive fully down into the areas that you really want to request more data for initially.

Communication:

Interviewers care about the reason and thinking as much as about the content itself. It's important to explain your framework well, however, you don't need to provide a detailed explanation for every idea in your framework, especially if it is obvious why it is there.

Hope this helps!

Cheers,

Florian

Hi,

Here's my take: 

1) How to prioritize 80/20 while maintaining comprehensiveness 

I think there is a common misconception that candidates sometimes have on what 80/20 means w.r.t. being MECE as well. 

You have to first be MECE (or structured) before you can be 80/20. If you are not MECE, then you would struggle to figure out whether or not your prioritization is actually the best one (because you may be missing a lever/idea/hypothesis that is more relevant).

Sometimes you may get feedback that says your breakdown is not 80/20 - this could mean a few things but in my mind the most common struggle here is actually generating a breakdown or looking at a problem in an effective and insightful way. This means that there may have been another way of breaking down the problem that is more effective in helping you to achieve what you need to achieve (thus, 80/20).

In terms of how to think about 80/20, I would urge you to ask yourself always to think about what is the most important answer/point/hypothesis/lever w.r.t. to what you are trying to achieve. 

2) How can I make the interview more conversational?

A few tips from my experience sitting on both sides of the interview:

1. Pause at critical points and invite the interviewer to share their perspective
2. Acknowledge the information that you are being relayed/told 
3. Actively respond and build on information given to you - i.e. continuing the conversation

All the best!