Metrics question
The Facebook Stories engineering team has proposed doubling the height of the Stories widget. As the PM, what are the potential pros and cons of this change?
- Meta
- Metrics
- Hard
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What this question tests
Tests balanced impact analysis on a seemingly small UI change: can you weigh screen real estate trade-offs against content and engagement outcomes with specific reasoning.
How to approach it
- Clarify the change: doubling the Stories widget height means more space for Stories previews and fewer feed posts visible without scrolling.
- List potential pros: more Stories visibility likely drives more views and creation, since discoverability strongly predicts usage.
- List potential cons: it pushes feed content further down, so users see fewer posts per scroll, which could reduce feed engagement and ad impressions.
- Identify a secondary con: a larger persistent widget takes more space on smaller devices, potentially crowding the experience.
- Propose how to decide: run an A/B test comparing Stories engagement lift against any feed engagement or ad-impression decline.
- Define the metric to watch: net platform time-spent and net ad revenue, not Stories engagement alone, since a component win could be a platform loss.
What a strong answer includes
- Names a concrete revenue trade-off explicitly, that pushing feed content down could reduce feed ad impressions, a real cost of this change.
- Distinguishes component-level metrics from platform-level metrics, correctly framing why this needs a net analysis, not Stories engagement alone.
- Proposes a concrete test method, an A/B test, rather than a purely qualitative judgment on a measurable trade-off.
- Flags a secondary UX cost, device clutter on smaller screens, beyond the pure engagement trade-off.
Common mistakes
- Listing only pros or only cons without weighing them against each other.
- Ignoring the ad-revenue implication of pushing feed content further down the screen.
- No proposal for how to actually validate the change (A/B test) before a full rollout.
Likely follow-up questions
- How would you design the A/B test to isolate the effect on feed engagement specifically?
- What would you do if Stories views increased but overall time spent decreased?
- How would this trade-off differ on a small-screen phone versus a larger one?
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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