Segments must be actionable to be useful. Can the marketing team actually target them? Can the product team build features for them? If not, simplify until they can.
Strong answers cover: defining segmentation goals (marketing targeting, product prioritisation, pricing), choosing variables, analytical methods (RFM, clustering, behavioural cohorts), validating segments against real outcomes, and making segments usable by non-analytical teams. Best candidates discuss the trade-off between statistical sophistication and practical utility.
Tests analytical depth and practical judgment. Analysts who produce statistically elegant but practically useless segments are solving the wrong problem. Ask: "How did the business actually use the segments you created?"