Purpose: The purpose of the Learning from Critical Incidents and Peer Assessment Toolkit is to help users analyze the response to an emergency via a process that focuses on public health systems root causes of failures and/or successes in the response. Tool Description: This toolkit was created to aid public health officials in improving a public health systems level of preparedness. It uses peer assessment, root cause analysis and other methods to teach users how to properly respond based on experience from previous events. The toolkit consists of three components: 1. Online Training (teaches users how to use the toolkit) 2. Case Studies (teaches users root cause analysis) 3. Manual and Supporting Materials A.K.A Peer Assessment Toolkit (teaches users how to generate reports that describe lessons learned) Who should use it?: The Learning from Critical Incidents and Peer Assessment Toolkit was designed to be used by public health officials, particularly those conducting after-action reports. Benefits: The analysis of the response to public health emergencies is often undermined by a failure to identify the root causes of specific failures and/or successes. This is largely due to a lack of knowledge of proper protocols that allow public health systems to do so. However, by teaching users how to analyze root causes and combining that information with previous case studies, the Learning from Critical Incidents and Peer Assessment Toolkit has the potential to contribute to system improvement efforts. The use of this toolkit can improve an evaluators ability to write useful after action reports.