The most basic dynamic in the simulation is the process of getting work done. The scope of the project leads to a list of work to be done. This work takes the form of activities assigned to resources. The level and type resources available for the project are determined by 1) the overall size of the work to be done 2) the project schedule and budget and 3) any organization constraints (like headcount). The resources start working on the activities thus increasing activity completion. As they do this, the amount of work to be done diminishes. This is a balancing or goal-seeking feedback loop where the goal is to drive the work to be done to zero (i.e., to complete all of the activities in the scope). The outer feedback loop is also a balancing loop. It represents the process by which the project manager balances the team size with overall size of the project, the scheduled completion and the budget.