Why has Zoopla's "Instant Valuation" feature experienced a 40% increase in error rates during peak hours in the past two weeks?

Introduction

Zoopla's "Instant Valuation" feature experiencing a 40% increase in error rates during peak hours over the past two weeks is a critical issue that demands immediate attention. This analysis will systematically identify, validate, and address the root cause while considering both short-term fixes and long-term implications for the product.

I'll approach this problem by first clarifying the context, then ruling out external factors before diving deep into the product mechanics, metric breakdown, and data analysis. From there, I'll form hypotheses, conduct root cause analysis, and propose validation methods and solutions.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking this could be related to recent changes. Have there been any product updates or system changes in the last month?

Why it matters: Recent changes often correlate with performance issues. Expected answer: Yes, there was a minor update to the valuation algorithm. Impact on approach: If yes, I'd focus on the changes made and their potential impact.

• Considering the peak hour specificity, I'm wondering about system load. Can you share details on server capacity and recent traffic patterns?

Why it matters: Peak hour issues often indicate capacity problems. Expected answer: Traffic has increased by 20% in the last month. Impact on approach: High traffic would lead me to investigate scalability solutions.

• Given the error rate increase, I'm curious about the nature of these errors. What types of errors are users experiencing?

Why it matters: Different error types point to different root causes. Expected answer: Mostly timeout errors and incorrect valuations. Impact on approach: This would guide my technical investigation focus.

• Noticing the two-week timeframe, I'm considering external factors. Have there been any significant market changes or competitor actions recently?

Why it matters: External factors can indirectly impact system performance. Expected answer: No major market shifts, but a competitor launched a similar feature. Impact on approach: This would influence whether I focus more on internal or external factors.