Once the WBS has been defined, we can create a schedule model that includes the tasks needed to produce the deliverables. We will define tasks, the order that the tasks will take place, and the durations or work for the tasks.

A well designed schedule model enables us to identify and quantify which tasks are most likely to cause us to miss our due date. We also use the schedule model as a schedule tracking and control mechanism, and to proactively identify and resolve potential problems.

The three main schedule model elements we will work with are:

• Tasks – also called activities – describe the work required to produce the deliverables for our project. Drawn as a bar in the Gantt Chart area.
• Milestones – key events for the project. They are used to identify the start or finish of a significant task or group of tasks. They are created in Microsoft Project as tasks with zero duration. Drawn as a diamond in the Gantt area.
• Links – also called dependencies – define the order that the tasks will take place. Drawn as an arrow in the Gantt Chart area.

Later, we will also assign resources to our schedule model.