Business Context

You are the Business Analyst supporting the Facebook App engagement team at Meta. In the weekly KPI review, leadership notices that Facebook DAU in the US/Canada fell sharply on Tuesday after being stable for the prior six weeks.

Metric Scenario

The dashboard shows US/Canada DAU dropped from 38.4M on Monday to 34.9M on Tuesday (-9.1%), while MAU remained flat at 196M. Average sessions per DAU declined from 5.8 to 5.1 (-12%), but average session length stayed roughly flat at 18.4 vs 18.1 minutes. The drop appears concentrated on Android (-15%); iOS is down only 2%, and Web is flat. At the same time, the product team launched a Facebook Feed ranking update to 20% of Android users on Monday evening, and the data engineering team notes a recent client logging SDK update for Android app version 462.0.

Leadership wants to know whether this is a real engagement issue, an instrumentation problem, or a dashboard/query bug, and they need an initial root-cause assessment by end of day.

Requirements

1. Define the DAU metric precisely, including inclusion/exclusion rules and edge cases.
2. Lay out a structured investigation plan to determine whether the anomaly is caused by product behavior, logging issues, or reporting logic.
3. Decompose the metric into components and segments to isolate the driver of the drop.
4. State the top hypotheses you would test first and what evidence would confirm or reject each.
5. Recommend immediate next steps and guardrails for stakeholders if the anomaly is real.

Data Available

• facebook_app_events
• feed_impressions
• user_sessions
• app_version_dim
• experiment_exposure_log
• dashboard_metric_history
• etl_job_runs