The master project schedule is created from the project plan and individual schedules. Creating the master project schedule will give the team an overview of what needs to be done, when it needs to be done and when it should be completed. The master project schedule should take into account all fixed schedules. Below is a brief how-to guide, intended to instruct you on how to create a successful master project schedule.The master project schedule allows the project manager to monitor the progress of the project toward the completion of important milestones.
Step 1: Obtain the Project Plan and Individual Schedules
Because the master project schedule is created from the project plan and an aggregate of the individual schedules, the first step is to obtain these documents. If a master project schedule is being created for all current projects, then the project manager will require the project plans for each of these projects and the individual schedules for each of these projects. Once this information is obtained, the master project schedule can begin.
Step 2: Begin Scheduling from the Bottom-Up
If you begin from the bottom, the latest deadline and work your way back, it will be more accurate. Begin with the deadline of the final project deliverable. In fact, if you know the deadlines for each milestone, enter these into the master project schedule and work backward. For information on bottom-up scheduling, see my article, "Decomposition and Bottom-Up Estimation."
Step 3: Schedule Intermediate Tasks
Once you have entered in the fixed deadlines for the project, you can begin to fill the intermediate task schedule. To do this, refer to your resource information. This is where you will take their individual schedules and limitations into account. Once you have this information, fill in deadlines for intermediate tasks with the individual assignments.
Step 4: Don’t Forget to Include Padding
Build padding into task deadlines to prevent disaster. One way to pad project tasks to create a realistic schedule is to use the PERT Formula for estimating durations. You can use one of two figures – either the figure the formula gives you, or on tasks that involve risk, the "Worst case scenario" estimate for duration. For information on using the PERT Formula in project management, see my series.
Step 5: Save the Master Project Schedule
Once the schedule is created and the timing issues have all been resolved, save it. This schedule is not to be modified. It will be used to inform upper management of time expectation of your project. It will also be used in order to make decisions when scheduling changes must occur. Think of the Master Project Schedule as an unalterable, unchanging project document. Make sure to keep a backup copy of it, just in case you accidentally save over it.