According to the CRISC Review Manual1, lessons learned from materialized risk scenarios are the insights and knowledge gained from analyzing the causes, impacts, and responses of actual risk events that occurred in the past. Lessons learned from materialized risk scenarios are the most helpful resource when creating a manageable set of IT risk scenarios, as they help to identify and prioritize the most relevant and realistic risks that could affect the organization's objectives, processes, and resources. Lessons learned from materialized risk scenarios also helpto improve the risk management practices and capabilities, and to avoid repeating the same mistakes or gaps in the future. References = CRISC Review Manual1, page 206.