1. Validate telemetry: check for logging outages, pipeline delays, or metric definition changes. 2. Segment by dimensions: decompose the drop across geography, client platform (iOS vs Android), app versions, user cohorts (new, resurrected, core users), and network connections. 3. External vs Internal factors: did an external event occur (holidays, ISP outages, app store takedowns) or an internal shift (app release, bad experiment rollout, algorithm update)? 4. Funnel inspection: check login conversion, crash rates, and engagement depth (time spent, stories viewed). 5. Formulate hypotheses, isolate the root cause, and present findings with recommended engineering remediations.