Metrics question
Imagine you're the product manager for Facebook Marketplace. Since many sellers don't mark items as sold, what existing functionality and metrics could you use to determine whether an item has likely sold?
- Meta
- Metrics
- Hard
Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.
Start a mock interview on this question · Mock interview from a job description
What this question tests
Ability to infer signals from indirect data when the direct answer (an item sold) is not explicitly tracked.
How to approach it
- State the problem clearly: sellers often do not mark items sold, so the true active inventory is unknown.
- Identify indirect signals: the listing is removed by the seller, the seller stops responding to messages, or repeated buyer reports say it is unavailable.
- Use behavioral signals: a sharp drop in views or messages after a period of high interest can suggest the item left the market.
- Propose a model combining these signals, for example seller inactivity plus buyer 'still available' report rate, to score likely sold status.
- Validate the model against a small sample of manually confirmed sold or unsold items to check accuracy.
- Define success as the model's precision at flagging sold items and reduction in buyer complaints about unavailable listings.
What a strong answer includes
- Names specific, concrete signals, seller responsiveness drop and buyer unavailability reports, rather than a vague 'use engagement data'.
- Proposes combining multiple weak signals into a single score, which is how real marketplace trust models work.
- Gives an illustrative number, e.g. assumes seller non-response for 7 days after a message correlates with 70 percent sold likelihood.
- Proposes validating the model against a manually labeled sample before trusting it at scale.
Common mistakes
- Proposing to just ask sellers to mark items sold, ignoring that the question states many will not comply.
- Not proposing any way to validate the inferred signal against ground truth.
- Relying on a single weak signal instead of combining multiple indicators.
Likely follow-up questions
- How would you validate this model is actually accurate?
- What would you do with items the model is uncertain about?
- How would you incentivize sellers to mark items sold directly?
More metrics questions
- How would you measure the success of Facebook Likes?Meta · Metrics · Medium
- How would you measure improvements made to Facebook messenger?Meta · Metrics · Easy
- Imagine you are the PM in charge of Reactions on Facebook - the new way to interact with posts by using “love”, “haha”, “wow”, “sad”, and “angry” reactions. What would success look like in terms of number of non-like reactions per post at launch and how do you come up with this? Would this number differ by reaction? Why or why not?Meta · Metrics · Hard
- You launched a new signup flow to encourage new users to add more profile information. A/B test results indicate that the % of people that added more information increased by 8%. However, 7 day retention decreased by 2%. What do you do?Google · Metrics · Hard
- Define the metrics for YouTube search.Google · Metrics · Medium
- You are the PM of Instagram app. The MAU has been constant but DAU has declined. What will you do?Meta · Metrics · Medium
More questions from Meta
Learn the skill behind it
Chapters of the AI PM course that teach what this question tests.
- Chapter 9: Prove it paid off: outcomes, economics, and pricing
- Chapter 2: Data fluency: SQL, logs, and reading the truth yourself
- Chapter 14: Get the job: the AI PM interview loop