The Case of the Misnamed Cities: CAST Analysis of a Google Maps Incident

Traditional Root Cause Analysis (RCA) is inadequate for learning from complex software incidents, often resulting in only proximal, sharp-end mitigations. For the past three years at Google, we have successfully applied Causal Analysis based on Systems Theory (CAST) to analyze major incidents. In this talk I will demonstrate the power of CAST using a real incident involving incorrect data being displayed to external users. I will contrast the findings of the original postmortem, which focused on the proximal chain of events, with the CAST analysis, which uncovered deeper, systemic environmental factors. I will show you how we use CAST to identify blunt-end systemic factors and translate those insights into recommendations that deliver durable safety improvements.