The PERC manual – Learning from disasters to build resilience: A guide to conducting a Post-Event Review 2020

The Post-Event Review Capability (PERC), which was launched in 2013 by the Zurich Flood Resilience Alliance,  provides a process and framework for the systematic analysis of a disaster event, focusing on how a specific hazard event became a disaster.

PERC builds on the field of disaster forensics to systematically and holistically analyze disaster events and what led to them, and to identify actionable recommendations. It is typically conducted and published within a year of the event, though it can be used in other ways or in other timeframes as necessary.

PERC evaluates the successes and failures in the management of disaster risk prior to the event, disaster response, and post-disaster recovery. If the event occurred in two different areas with one more severely impacted than the other, PERC can help determine why the impacts were disproportionate. PERC then identifies future opportunities for intervention/action that could reduce the risk posed by the occurrence of similar, future hazard events. PERC uses a system-wide approach to review disasters, analyzing across scales and sectors, and all five aspects of the disaster risk management cycle—prospective and corrective risk reduction, preparedness, response, and recovery. It provides a bird’s-eye view of why the event manifested in the way it did and how resilience might be built.

While most PERCs to-date have primarily focused on floods, the PERC can be applied to review any rapid-onset shock, natural or non-natural, such as floods, earthquakes, tsunamis, terrorist attacks, and so on. To date, 18 PERCs have been conducted on a variety of flood types including river floods, flash floods and tropical and winter storms that led to catastrophic flooding in both urban and rural settings and in global contexts ranging from least-developed to most-developed. In addition, the methodology has recently been expanded to include three reviews of wildfire events.