MECE: Directional not Absolute
One rule of thumb for product case interviews is the idea of MECE (mutually exclusive, collectively exhaustive) groupings of users. This is ‘directionally correct’ advice. However it should not be forced at the expense of strong groupings that are not perfectly MECE.
Lately, I have seen an increases of PMs tying themselves in knots to come up with MECE groupings and so they end up with segments or groupings of users that are so mutually exclusive that it sounds awkward.
It is better to have a little overlap. Think: planner vs seat-of-your-pants approach with the average in the middle is better than picking farmer, plumber and doctor. Use common sense. What we are doing during a case interview is showing empathy with users, not following rules of thumb as the absolute end-all be all.
It is most important to show that you can think about different users and their different mindsets.
To learn more about user segmentation, read the following blog entries:
