What factors are causing the sudden increase in failed transactions for NatWest's Faster Payments service this quarter?

Introduction

The sudden increase in failed transactions for NatWest's Faster Payments service this quarter 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 service.

I'll approach this problem by first clarifying key details, ruling out external factors, and then diving deep into the product ecosystem, metric breakdown, and data analysis. From there, I'll generate and validate hypotheses, conduct root cause analysis, and propose a comprehensive resolution plan.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking there might be a recent system change. Has there been any significant update to the Faster Payments infrastructure in the last quarter?

Why it matters: System changes often correlate with performance issues. Expected answer: Yes, there was a major upgrade to the payment processing engine. Impact on approach: If confirmed, I'd focus on post-deployment issues and rollback considerations.

• Considering user segments, I'm curious about the distribution of failed transactions. Are we seeing a higher failure rate for particular transaction types or amounts?

Why it matters: This could indicate whether the issue is systemic or specific to certain use cases. Expected answer: There's a higher failure rate for transactions over £10,000. Impact on approach: I'd investigate potential issues with high-value transaction processing.

• Given the nature of Faster Payments, I'm wondering about the timing of failures. Is there a pattern in terms of day of week or time of day when failures are more frequent?

Why it matters: This could point to capacity issues during peak times or scheduled maintenance windows. Expected answer: Failures spike during weekday evenings. Impact on approach: I'd look into evening traffic patterns and potential capacity constraints.

• Thinking about external factors, have there been any recent regulatory changes affecting Faster Payments or interbank transfers?

Why it matters: Regulatory changes can sometimes lead to implementation challenges. Expected answer: No significant regulatory changes in the past quarter. Impact on approach: I'd focus more on internal factors rather than regulatory compliance issues.