First of all, the bar for your performance on the PEI and the case sections will be the same, regardless of whether you have experience at another consulting firm or not. The only time that could vary is if you were an experienced hire / expert hire with many years of experience. In that case, the fit / behavioral bar would likely be higher and the case interview bar could be a bit lower.
In terms of using your previous consulting experience for your PEI answers, the answer is “it depends”. In general, you should be looking for the best answers / stories / situations that answer the question the interviewer is asking. Almost any experience can be successful during the PEI portion of the interview as long as it addresses some of the following attributes:
- Influencing: Does the candidate accurately anticipate or react to the need for various influencing tactics and deploy them appropriately
- Drive / Achieving: Has the candidate demonstrated a passion for setting challenging goals and achieving them in a practical way?
- Leadership: Has the candidate demonstrated inspiring leadership, sensitivity to others and an ability to help teams succeed in the face of challenge?
- Teamwork: Has the candidate shown deep insight into the whole team effectiveness and taken action to improve it (e.g., actively coaches, resolves conflict)
- Empathy: Does the candidates behaviors, plans and actions demonstrate an awareness and understanding of the thoughts and feelings of others?
- Learning: Does the candidate show an sufficient level of intellectual curiosity and extract learnings from experiences?
I find it most helpful when candidates try to mix in a non-work experience into a least one of your PEI interviews. By using a non-work situation, you are able to:
- Stand-out: Remember that there is a decision meeting about whether you pass to the next round (if it’s a first round interview) or get an offer (if it’s a final round interview) and the more you stand out as a candidate, the easier it is to “make the case” for you during that meeting. I can remember to this day dozens of non-work PEI experiences that didn’t involve work, but not a single one that did involve work.
- Add humor: You can tell your story and add a twist of humor to it. Interviewers have long, mundane days of interviewing and like to have the mood lightened.
- Add personal depth: Show that you have skills and interests outside of work. If you happen to hit upon a story that resonates with the interviewers past experiences or interests, that’s a home run!
Having led many decision meetings (1st and final rounds) as a Partner at McKinsey, let me give you a little insight into how the meetings actually happen. A tired group of interviewers convene at the end of the day with all of their notes. The decision meeting leader begins pulling up the candidates info one by one. The interviewers are trying to think back to the candidate and looking at their notes (which are not very detailed). The interviews give a recap of what they taught and actually oftentimes playback a PEI story if, and only if, it was interesting before a final decision is made. This is why it is key to pick the right stories and often times, a non-work story or two.
Going back to the case interview, there is really going to be no difference. If anything, the interviewer may think that you should be more polished on the case than other candidates since you have previously worked in consulting.