How to formulate high-quality lessons learned: a rapid review.

Lessons learned convey information and experiences that were studied when carrying out projects or policies, in order to improve procedures and practices to better cope with future similar problems in other contexts. Although the term lessons learned appears in the titles of thousands of scientific articles, most do not describe how these lessons were produced or the level of rigor involved in their development. As part of a project aimed at deriving lessons from hospitals' resilience during the COVID-19 pandemic in five countries (the HoSPiCOVID project), we sought to systematised the process of producing these lessons. To do so, we conducted a rapid review to identify the best ways of developing quality lessons learned (QLLs). A QLL results from a systematic process of collecting, compiling, and analysing data derived from a research project. The rapid review follows the same key steps as a systematic review, adapted to a more accelerated and pragmatic format. From 1,881 documents initially identified, 18 were retained. Their analysis identified three principles to guide the process of developing QLLs: 1) Creating a supportive climate; 2) Choosing the right leaders or facilitators for the process; and 3) Engaging in a scientific approach. Based on these findings, we developed a guide comprising 11 steps, structured into two main phases: preparatory steps for QLL development, and steps for identifying and formulating QLLs. This guide offers a structured process for teams seeking to enhance the rigor, clarity, and potential transferability of the lessons they formulate.