Decide to ship a signup experiment
Company: Upstart
Role: Data Scientist
Category: Analytics & Experimentation
Difficulty: hard
Interview Round: Technical Screen
You receive results for an A/B experiment on a redesigned user signup flow. Data file columns: variant (A/B), sessions, signups, activation_d7, p95_latency_ms, support_tickets, refund_rate, and revenue_d30. Describe exactly how you would: (1) validate data quality (SRM test, bucketing integrity, exposure logs vs analytics counts); (2) choose primary and guardrail metrics and justify them; (3) compute effects with CIs (include ratio metrics and non-parametric options if skewed), and apply variance reduction (e.g., CUPED) if appropriate; (4) check power/min detectable effect and whether the observed duration met the pre-registered stopping rule; (5) evaluate novelty and learning effects (time-sliced and cohort views); (6) make the ship/no-ship call with a concrete decision framework that balances activation gains vs increased latency/support tickets; (7) list at least three additional insights to extract beyond the ship decision (e.g., segment heterogeneity by traffic source/device, step-drop analysis, form-field sensitivity). Be precise about formulas, tests, and thresholds you would use.
Quick Answer: This question evaluates A/B testing and experimentation competencies, including data quality validation, metric selection, statistical estimation, power analysis, temporal and cohort effects, and decision-making trade-offs, and it falls under the Analytics & Experimentation domain for Data Scientist roles.