According to the PMBOK® Guide, the formal gathering, ritualization, and archiving of lessons learned documentation is a primary activity of the Closing Process Group (specifically within the Close Project or Phase process).
While modern project management encourages the continuous recording of lessons learned throughout the project lifecycle (to the Lessons Learned Register), the formalization of these documents for the benefit of the organization occurs during Closing.
Final Archive: During the Closing phase, the project manager reviews all previous documentation to ensure that all " knowledge gained " is finalized.
Organizational Process Assets (OPAs): The primary output of this activity is an update to the Corporate Knowledge Base. This ensures that future project managers can benefit from the successes and failures of the current project.
Administrative Closure: This involves documenting the reasons for any deviations from the original plan and the effectiveness of the risk responses implemented.
A. Planning: This group focuses on defining the course of action. While you might review lessons learned from past projects here, you are not yet gathering them for the current project.
B. Executing: During execution, the team is performing the work. While the Lessons Learned Register (a project document) is updated during execution, the " Lessons Learned Documentation " as a formal project closure deliverable is a function of the Closing group.
D. Initiating: This group is for authorizing the project. At this stage, there is no project performance to reflect upon or document.
In the most recent editions of the PMBOK® Guide, there is a distinction between:
Lessons Learned Register: An active document used throughout the project (Executing/Monitoring).
Lessons Learned Repository: The final resting place for the documentation after the project is closed (Closing).
For the purpose of this examination, the act of " gathering " the final documentation for organizational use is strictly tied to the Closing of the project or phase.
