let me share an experience that I had during my first round at McKinsey; the practice I applied to was specifically on Oil&Gas (I did a master on Energy Economics), therefore I found natural to prepare on that and develop “business acumen” in the sector. I spent time reading a lot of material related to such a practice, including reports and blogs, and believed had a very good knowledge when I approached the day of the interview.
Then the day of the interview arrived, and instead of an Oil&Gas cases I got a completely different industry I was not familiar with. I managed though to spend enough time at the beginning to ask the right questions to clarify the industry. Once understood how that particular industry worked, I applied a proper framework, and managed to derive the right conclusion.
Thus, in my experience what is fundamental to crack a case is not much “business acumen”, but mainly two specific things:
- Your ability to ask the right questions at the beginning
- You knowledge of the right frameworks to use (for right frameworks I do NOT mean the standard ones in Case in point or Victor Cheng, which most of the time are too vague)
This is not to say that it is a completely waste of time to read books, blogs or reports on specific industries – such material may be indeed be useful; however it is probably not the best usage of your time to maximize the outcome of your next interviews.
What can you then do to improve? The definitive best thing you can do is what Vlad and Nuno have mentioned as #1 – Cases. So far that you manage to read in the right way 100+ cases you can be sure you will find a comparable scenario in your interview (for right way, I mean you don’t just read passively them, but try to think how to structure them before going through the solution). Then, if you ask the right questions as for step 1 above and apply the right framework as for step 2, you will be able to crack the case, even if you do not have specific knowledge of the industry.
As for your specific case, I agree with Nuno – a feedback mentioning “lack of business acumen” is not very explicative anyway. It is likely there are some specific areas you can improve doing cases – clarifying questions, structuring, graph interpretation – and the interviewer summarized it as lack of business acumen. As it is difficult for you to identify alone which was the issue, the best thing would be to find a proper partner for interviews, able to pinpoint the potential improvements that you have to concentrate on. This will help to derive what they actually meant with “lack of business acumen” and take the specific steps to avoid repeating such mistake. It is very likely that once fixed it, you will not need to read additional books/reports, but only read more cases in order to succeed in your next interview.