Choose a North-Star Metric for a Marketplace

What interviewers evaluate

• Do you pick a match/transaction-quality north star rather than GMV or user counts?
• Do you define liquidity from both sides (demand fill rate, supply utilization)?
• Do you use the two sides to identify which one is the binding constraint?
• Do you measure per market cell (geo × category × time) instead of trusting averages?
• Do you include economic and quality guardrails (subsidized liquidity isn't durable)?

A framework to structure your answer

1. North star - successful matches meeting a quality bar (completed transaction within a time/experience threshold), not GMV or signups.

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