No. Mention an outlier when it could change the interpretation or decision, not simply to prove that you saw it.

Good data analysis is selective. Interviewers want the insight that matters for the case, not a complete narration of every visual feature. Irrelevant observations can dilute the main message.

If one region has unusually high growth but represents only 1% of revenue, it may not deserve much airtime unless the case is about future growth opportunities. A margin collapse in the client's largest region would be far more decision-relevant.

After spotting an outlier, ask: 'So what for the client's objective?' If you cannot explain the implication, keep it in your notes and lead with the observations that actually affect the recommendation. If useful, this guide on case interview insight generation gives more detail.

Not every outlier deserves airtime. The 'so what' test helps a lot.