McKinsey, BCG, Bain and Roland Berger use similar but not the same case styles. Within even one firm, styles may differ. Each firm uses a very different interview style. We discuss the different styles to expect and how to handle the questions you will encounter. We also rank the difficulty of the cases from each firm. Expect some counter-intuitive ordering.
Cases can be interviewer led or interviewee led.
Cases be answer-first or not answer first.
Cases can have the objective function to solve or lack an objective function.
Cases may require a framework or not require a framework.
Different firms or interviewers can pull cases together with different components since these are all mutually exclusive:
Additional podcasts describes this in much more detail.