Marketplace activation drop
Practice turning a product metric drop into clarifying questions, metrics, grain choices, and tradeoff communication.
Concept
fact-table-grain
The primary modeling idea this problem reinforces.
Requirements
4
Business needs the model must satisfy.
A marketplace team says listing activation dropped after a seller onboarding change. The interviewer asks you to define the metrics, design the model, and explain how you would debug whether the drop came from seller mix, category changes, listing quality, or purchase conversion.
This is the bridge from guided concept practice to interview mode. The schema matters, but the verdict depends on whether the candidate clarifies the product question, defends grain, and explains tradeoffs.
- Define listing activation numerator, denominator, time window, and exclusions.
- Propose facts and dimensions that support activation, purchase conversion, seller mix, and category breakdowns.
- State where seller or category history matters and how the model preserves it.
- Explain at least one simpler alternative and when it would be acceptable.
- Define listing activation and purchase conversion metrics before schema design.
- Separate listing lifecycle events from purchase conversion facts.
- Explain seller/category history choices and production debugging concerns.
Try the question first.
The discussion has other people's approaches and solutions. Give it a real attempt before you read them.