Here's a question that may be on a lot of people's minds but which I haven't seen addressed on your site or in the daily e-mails:
If you recognize a flaw or a gap in your approach or framework just after the case interview is over, is there any value in addressing this in your subsequent thank you note to the interviewer?
For example, as I was doing the post-mortem in my head, I realized I had neglected to ask a pretty important question in an M&A case, so I was tempted to acknowledge this omission in my thank you note, while explaining why it should have been addressed.
The hope would be to positively influence the interviewer's impression of my performance before he compares notes with his colleagues.
Certainly there would be no expectation of "full credit" for fixing what you should have gotten right the first time, but at the same time, it's hard to imagine this would hurt.
Would this hurt? Probably not.
Will it help? It won't.
Most interviewers are doing back-to-back interviews all day long. Once they are done and once the information is fresh in their heads, they usually meet as a group, compare notes and make decisions.
So the firm's decision to continue with you or not is generally made before anyone has had time to check their emails.
In some cases, even if the candidate realized their error before the end of the case and addressed it, often this does not alter the decision.
There are certain aspects of a good case interview performance that need to occur at the right time. Part of doing it the "right" way, is to do the right things at the right time.
You mix the batter for the cake, then you bake the cake. If you bake the cake pan, bake the contents of the pan, and then you realize you forgot to mix all the ingredients in the cake pan, it is too late.
You can't just mix the ingredients now, because all you have is a big mess.
The individual interviewer's decision was made the minute your interview ended (and often much sooner in the interview if you made some kind of glaring, very common error -- like the ones cataloged in the Look Over My Shoulder® program).
Basically if you make one of these type of mistakes at say the 11th minute of the interview, the interviewer's decision to reject you was made at the 12th minute of the interview.
The rest of the interview is really just a matter of the interviewer being polite.
As a former McKinsey interviewer, let me tell you (and this might sound a little harsh, but it is true):
These interviews are a bit boring for the interviewer. You know the candidate just blew the interview (made a major mistake), but they don't know it yet.
So it is painful to watch.
Or sometimes they will make a very deadly kind of minor (in magnitude), but important (in impact), error early in the case. And as an interviewer you know, you just know, they are going to screw up the case later in the process.
Let me give you an example. I can often see how a candidate takes notes in the first five minutes of a case, and based on nothing more than observing how they take notes, I can predict with probably 75% accuracy whether or not they are going to pass the case study interview.
Note, I don't need to see what they write, only how they write it.
If you're curious as to how I can tell, basically if the case involves an issue tree type situation and they don't draw an issue tree diagram and instead take notes verbally, the odds of missing something important in the case goes up considerably.
If you notice the issue tree diagrams in Look Over My Shoulder® cases #2, #4 and #5 (the final example in each), you'll notice how my style of note taking is:
1) Very clear
2) Virtually impossible to forget "where" you are in the case
3) Forces you to be hypothesis-focused
4) Makes it really easy to synthesize, because all the key synthesis points are already pre-marked in your notes along the way (without even really trying to do so)
You'll also note what is not in those primary set of notes. What's not there are calculations. I always do calculations on a separate piece of paper, but I keep the logic of my case on my primary note pad.
One of the reasons why my thinking is so structured (that word interviewers like), is because my note taking is structured.
For more information on preparing for a case interview, access my free video series on Case Interview Secrets .