Design metrics and experiment
Company: Other
Role: Data Scientist
Category: Analytics & Experimentation
Difficulty: hard
Interview Round: Technical Screen
Design success metrics and an experiment for the new subscriber-only feature to achieve your chosen goal. Specify: (1) precise primary metric(s) and units (e.g., 28‑day subscriber churn, free→paid conversion within 14 days, ARPU net of discounts); (2) guardrails (e.g., complaint rate, time-to-render, refund rate, non-subscriber engagement); (3) segmentation (new vs existing subscribers, price tiers, geos), plus how you’ll handle heterogeneous treatment effects; (4) event instrumentation and attribution windows; (5) experiment unit, randomization, sample size and power for your chosen MDE, and a staged ramp plan; (6) how you’ll treat non-subscribers who upgrade mid-test (intention-to-treat vs per-protocol), crossovers, and novelty effects; (7) how to detect and cap cannibalization of other revenue; (8) a difference-in-differences or synthetic control fallback if an RCT is infeasible.
Quick Answer: This question evaluates a candidate's competency in experimental design, success-metric definition, event instrumentation, causal inference for heterogeneous treatment effects, and statistical power and sample-size calculations for subscription-product analytics.