##### Scenario A ride-hailing company just updated its rider ETA-prediction algorithm and wants to quantify the marketplace impact. ##### Question Design an experiment to measure how the new rider-ETA model affects the business. Which primary success metrics would you track on the demand and supply sides? What intermediate or leading indicators would you monitor? Would you pick a classic A/B test or a synthetic-control approach? Explain the design, randomization unit, duration, and how you would interpret results. ##### Hints Map customer → marketplace funnel, define guardrail KPIs, consider network interference, seasonality, and statistical power before choosing between parallel A/B and geo-level synthetic control.