Why has Netflix download speed decreased by 50% on mobile devices?

Introduction

Netflix's mobile download speed decrease by 50% is a critical issue that demands immediate attention. This significant performance drop could severely impact user experience, retention, and ultimately, the company's bottom line. I'll approach this problem systematically, focusing on identifying the root cause, validating hypotheses, and developing both short-term fixes and long-term solutions.

Step 1

Clarifying Questions (3 minutes)

• Looking at the scope, I'm thinking this might be a global issue. Is the 50% decrease observed across all regions or specific to certain markets?

Why it matters: Helps determine if it's a localized problem or a global infrastructure issue. Expected answer: It's a global issue affecting all markets. Impact on approach: If global, we'd focus on core infrastructure; if localized, we'd investigate regional factors.

• Considering recent changes, I'm wondering if there have been any major app updates or server-side changes in the last 30 days?

Why it matters: Recent changes often correlate with performance issues. Expected answer: A server-side content delivery optimization was implemented two weeks ago. Impact on approach: This would shift our focus to the recent optimization as a potential cause.

• Thinking about user segments, are all types of content (movies, series, etc.) equally affected by this slowdown?

Why it matters: Helps identify if the issue is content-specific or universal. Expected answer: The slowdown is consistent across all content types. Impact on approach: If consistent, we'd look at underlying infrastructure; if varied, we'd investigate content-specific factors.

• Considering measurement accuracy, has there been any change in how download speed is measured or reported in the last month?

Why it matters: Ensures we're not dealing with a measurement anomaly rather than an actual performance issue. Expected answer: No changes in measurement methodology or reporting systems. Impact on approach: If changed, we'd need to validate the new measurement system; if not, we can focus on actual performance factors.