A project post-mortem is a process used to identify the causes of a project failure (or significant business-impairing downtime), and how to prevent them in the future. This is different from a Retrospective, in which both positive and negative things are reviewed for a project. The Project Management Body of Knowledge (PMBOK) refers to the process as lessons learned. Project post-mortems are intended to inform process improvements which mitigate future risks and to promote iterative best practices. Post-mortems are often considered a key component of, and ongoing precursor to, effective risk management. Source: Wikipedia (en)