I started with segmentation, which felt right, breaking it down by surface (home, search, browse), device type, user cohort.
Start by clarifying the metric definition and scope of the drop, then systematically segment the data to isolate the cause. Prioritize hypotheses, validate with data, and propose a response that includes immediate fixes and long-term experimentation.
Pro tip: Always tie the investigation back to business impact and user experience—interviewers want to see that you can balance data rigor with product intuition. Also, mention that you'd check if the drop is real or a tracking issue before diving deep.
Confirm how click-through rate (CTR) is defined, the time period, and whether the drop is statistically significant. Check for data pipeline or tracking errors that could cause a false alarm.
Break down CTR by dimensions such as platform, user cohort, geography, content type, and traffic source to identify where the drop is concentrated. Use funnel analysis to see if the drop occurs at impression, click, or post-click stages.
Brainstorm potential causes (e.g., UI changes, algorithm updates, seasonality, competitor actions, external events) and rank them by likelihood and impact. Cross-reference with recent product releases or market changes.
Use A/B tests, cohort analysis, or holdout groups to confirm the root cause. If a recent change is suspected, analyze its correlation with the drop and consider a rollback or fix.
Propose immediate mitigation (e.g., revert change, fix bug) and long-term improvements (e.g., redesign, algorithm tweak). Set up monitoring and follow-up experiments to ensure recovery and prevent recurrence.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.