Start with the biggest drop-off in your funnel. A 5% improvement at the highest-volume step produces more impact than a 20% improvement at a low-volume step.
Look for: data-driven identification of drop-off points (funnel analysis, heatmaps, session recordings), hypothesis formation, prioritisation frameworks (PIE or ICE), proper A/B testing methodology, and iteration. Best candidates discuss full-funnel CRO, not just landing pages, and mention the statistical requirements for valid tests.
Advanced marketing skill. Tests analytical rigour and systematic thinking. Ask: "What is the most surprising CRO test result you have seen?" to gauge depth of experience.