Each Project in Timing has a specific Productivity Rating assigned to it. To calculate your Productivity Score, Timing simply takes the average of all those Productivity Ratings weighted by the time you spend on the corresponding project. So if you spend e.g. two hours in a 100% project and one hour in a 25% productive project, your overall Productivity Score would be (2 hours * 100% + 1 hour * 25%) / (3 hours) = 75%. Accordingly, to make your personal Productivity Score as meaningful as possible, we recommend assigning as much time as possible to projects and setting productivity ratings for each project. Tip: select the "Unassigned" project on the Review and Details screens to only see activities that have not yet been assigned to a project.