One of the most important jobs of a project manager is to manage a project's budget and schedule. These tasks can easily be very difficult to accomplish on projects that are complex, especially since successful project execution relies heavily on people who are expected to perform their roles individually and as a team. One of the most difficult aspects of managing projects is estimating how fast and effectively humans will perform a task that is, determining how productive workers collectively will be each day, each week, or within any time period during the life of a project. Because projects are unique and are typically one-off endeavors, there is usually little previous empirical data to rely upon for the project manager to forecast productivity before or during the project's execution. The crux of the problem lies with adequately identifying not only the labor work flow process, but also the influences that affect the work flow process. When scope changes are introduced into the w