Abstract: A data processing system determines for all tasks in a project, material requirements and constraints, resource requirements and constraints, and a task uncertainty model. A task sequence and a critical chain are determined and an estimated project schedule including a project buffer is constructed. At the beginning of a project execution time interval the data processing system determines a criticality value for every task using the task uncertainty model, current criticality factor information, and task status information for tasks that are in-work. Project tasks are then prioritized based at least in part on task criticality. Tasks are assigned and executed and, at the end of the time interval, task status information is passed back to the data processing system for use in redetermining task criticality and reprioritizing the tasks for the next time interval.