How would you improve YouTube’s recommendation algorithm? – PM Interview Question

G → Goal / Clarify

Product Mission: YouTube’s mission is to help users find the content they love while helping creators build sustainable businesses.

Core Problem: Users may disengage if recommendations are repetitive, irrelevant, or low-quality, particularly for short-form content (Shorts) on mobile.

Clarifying Questions & Assumptions:

• Product Scope: YouTube main app (not YouTube Kids)
• Business Objective: Increase user engagement by 10% in 1 year
• User Segmentation: Focus on short-video consumers
• Platform: Mobile (iOS & Android)

Primary Metric (Success): Average Shorts Watch Time per User or D30 Retention for Shorts users

• This directly measures engagement, ensuring improvements in the recommendation algorithm lead to more relevant, engaging content consumption.

Guardrail Metric: Skip Rate / CTR on recommended Shorts

• Ensures higher engagement doesn’t come at the cost of user dissatisfaction or low-quality recommendations.

Refined Problem Statement:

Improve YouTube’s shorts recommendation algorithm on mobile to increase user engagement by 10% within one year, optimizing for average shorts watch time per user, while maintaining a positive user experience.

G → Audience & Pain Points

User Segments for Mobile Shorts:

New Users

• Limited watch history; rely heavily on trending or popular content.
• High potential for initial engagement but at risk of quick churn if recommendations are poor.

Casual Users

• Watch Shorts occasionally; engagement is intermittent.
• Likely to disengage if content becomes repetitive or irrelevant.

Power Users

• Frequent Shorts consumers; engage with a high volume of content daily.
• High lifetime value and significant influence on overall platform engagement.
• Sensitive to content diversity—repetitive or low-quality recommendations can lead to fatigue and reduced session time.

Why Power Users?

Disproportionate Impact: Power users contribute the majority of watch time and engagement metrics, so optimizing their experience yields high ROI.

Retention & Satisfaction: They are highly active and sensitive to repetitive or low-quality recommendations; improving their experience reduces churn.

Influence on Trends: Power users help shape content trends and influence algorithm signals, indirectly benefiting the broader user base.

Measurable Gains: Small improvements in their recommendations can lead to significant, immediate improvements in key metrics like average watch time and D30 retention.

U → Understand Pain Points (Power Users)

Repetitive Content

• Power users often see videos from the same creators or similar topics repeatedly, leading to boredom.

Limited Discovery of New Creators / Content

• Difficulty finding trending Shorts or new creators outside their usual watch history reduces exploration.

Low-Quality or Irrelevant Recommendations

• Clickbait or videos that don’t match interests can cause dissatisfaction and disengagement.

Algorithm Fatigue

• Over time, the recommendation feed can feel predictable or stale, decreasing long-term engagement.

Narrow Content Diversity

• Lack of variety in topics, formats, or creators limits the sense of novelty and discovery.

Overemphasis on Viral Content

• Algorithm may prioritize widely popular Shorts over niche content users might enjoy, reducing personalization.

Inconsistent Session Experience

• Recommendations may not adapt to user context (e.g., time of day or past viewing patterns), making sessions less engaging.

S → Solutions / Options (Power Users)

1. Discover New Creators Carousel
   • Add a dedicated section in the Shorts feed showcasing new creators and trending videos outside the user’s usual watch history.
   • Helps users explore more content and reduces boredom from repetitive recommendations.
2. Personalized Exploration Algorithm
   • Adjust the recommendation logic to balance familiar content with new content.
   • Slightly de-prioritize videos that are too similar to what the user already watches to maintain variety.
3. AI-Curated Shorts Playlists
   • Generate dynamic playlists for each user, mixing favorite creators with new, relevant content.
   • Keeps sessions engaging and encourages longer watch times.
4. Smart Shorts Reminders
   • Introduce subtle push notifications or in-app prompts highlighting new Shorts that match a user’s interests but are outside their usual watch patterns.
   • Encourages exploration and brings power users back to the app without overwhelming them.
5. Contextual Recommendations
   • Tailor recommendations based on time of day, past behavior, or session patterns.
   • Makes each session feel more relevant and engaging, improving overall retention.

Prioritization and Rationale:

1. Personalized Exploration Algorithm (Top Priority)

• Why: Directly addresses the core pain points of repetition and algorithm fatigue.
• Impact: Ensures power users get a balanced mix of familiar + novel content, keeping sessions fresh.
• Rationale: Improves engagement within the core feed itself (where users spend the most time), making it the highest ROI solution.

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2. AI-Curated Shorts Playlists

• Why: Builds on improved recommendations by curating structured, engaging sessions for users.
• Impact: Increases average watch time per session by reducing decision fatigue and making discovery feel effortless.
• Rationale: Helps power users go deeper into content, not just consume passively.

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3. Smart Shorts Reminders

• Why: Solves the problem of re-engagement outside the app.
• Impact: Nudges power users back into YouTube at the right moments with fresh, interest-aligned content.
• Rationale: Complements the first two solutions by extending engagement beyond the feed, boosting frequency of return sessions.

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✅ This prioritization balances:

• Core feed experience (Exploration Algorithm)
• Depth of sessions (Curated Playlists)
• Re-engagement (Smart Reminders)

S → Success Metrics & Trade-offs

Primary Success Metric

• Average Shorts Watch Time per Power User
  • Directly measures engagement depth and aligns with the goal of a 10% increase in 1 year.

Guardrail Metrics

• Skip Rate (ensure recommendations remain relevant).
• Content Quality Signals (likes/dislikes ratio, “not interested” feedback).
• User Retention (D30) (make sure engagement gains sustain over time).

Trade-offs

1. Personalized Exploration Algorithm
   • Opportunity Cost: Slower rollout of improvements for casual/new users.
   • Risk: Over-exploration could reduce short-term watch time if new content fails to engage.
2. AI-Curated Shorts Playlists
   • Opportunity Cost: Engineering and AI resources may be diverted from other discovery features.
   • Design Risk: Feeds may feel too “controlled” or repetitive if playlists don’t adapt well.
3. Smart Shorts Reminders
   • Opportunity Cost: Time spent building notification intelligence instead of core feed features.
   • Design Risk: Overuse of notifications could annoy users, leading to app fatigue or disabled notifications.

Summary

The problem we’re tackling is improving YouTube’s recommendation algorithm for Shorts on mobile, with the goal of driving a 10% increase in engagement from power users within 1 year.

Power users are the focus because they contribute disproportionately to watch time and retention, but are also the most sensitive to repetitive or low-quality recommendations. Their biggest pain points include content fatigue, limited discovery of new creators, and a lack of contextual variety.

To address this, I’d prioritize three solutions:

1. Personalized Exploration Algorithm – ensure a healthy balance between familiar and fresh content.
2. AI-Curated Shorts Playlists – dynamically mix favorite creators with new ones to keep sessions engaging.
3. Smart Shorts Reminders – nudge users back with timely, interest-based notifications.

We’d measure success primarily through average Shorts watch time per power user, with guardrails like skip rate, content quality signals, and D30 retention to ensure sustainable impact.

Overall, these improvements directly target content fatigue, encourage discovery of new creators, and make the experience feel fresh and relevant — aligning with YouTube’s mission to help users find what they love while enabling creators to grow.