Dr.Simon has mentioned multiple times the importance of this in his lectures. It is part of the project manager’s responsibility to create a log of some sorts which details everything that worked and everything that failed during the course of the project. This should be done during the closing phase of the project and stored in the Design History File as part of the organizational process assets. This will help project managers in the future understand your methods and plan their own course of action based off of your experience. Lots of time and money can be wasted by people repeating the mistakes of others attempting similar tasks in the same company. This is a very important principle but sometimes fails when people are lazy and will need to be passed on by word of mouth. This is an essential part of any closing phase that the members reflect on what happened.