DoorDash is considering allowing **bicycle couriers (bike dashers)** to fulfill deliveries in a city that is currently served mostly by car/scooter dashers. How would you evaluate whether adding bike dashers is a good idea? Please address all of the following: 1. **Historical analysis:** What historical marketplace data would you use to decide whether this city or specific zones are suitable for bike dashers? 2. **Success criteria:** What primary metrics, secondary metrics, and guardrail metrics would you track? Consider consumer experience, merchant experience, dasher experience, and unit economics. 3. **Experiment design:** How would you run an A/B test or marketplace experiment to estimate the causal impact of enabling bike dashers? 4. **Network effects / interference:** Adding bike dashers can affect dispatching and matching for all orders, not just treated ones. How would you handle these spillover effects in the experiment design and analysis? 5. **Decision-making:** What results would convince you to launch, limit, or roll back the change? Assume you have access to order-level, merchant-level, dasher-level, zone-level, dispatch, weather, and geography data.