The Integrated Master Schedule
As a document that integrates the planned work, the resources necessary to accomplish that work, and the associated budget, the IMS should be the focal point of program management. In this guide, an IMS constitutes a program schedule that includes the entire required scope of effort, including the effort necessary from all government, contractor, and other key parties for a program’s successful execution from start to finish.1
An IMS connects all the scheduled work of the government and the contractor in a network, or collection of logically linked sequences of activities. The sequences clearly show how related portions of work depend on one another, including the relationships between the government and contractors. Although the IMS includes all government, contractor, and external effort, the government program management office is ultimately responsible for its development and maintenance. In this respect, the government program management office must ensure that the schedule is as logical and realistic as possible. The IMS must be a complete and dynamic network. That is, the IMS should consist of logically related activities whose forecasted dates are automatically recalculated when activities change. If the schedule is not dynamic, planned activities will not react logically to changes, and the schedule will not be able to identify the consequences of changes or possible managerial action to respond to them.
In general, schedules can refer to programs and projects. In this guide, a “program” encompasses an entire program from beginning to end, including all government and contractor effort. An IMS may be made up of several or several hundred individual schedules that represent portions of effort within a program. These individual schedules are “projects” within the larger program. For example, a program IMS may consist of individual project schedules for the prime contractor, the government program management office, and a government testing laboratory.
As discussed in Best Practice 1, the IMS includes summary, intermediate, and all detailed schedules. At the highest level, the summary schedule provides a strategic view of the activities and milestones necessary to start and complete a program. The intermediate schedule includes all information displayed in the summary schedule, as well as key program activities and milestones that show the important steps in achieving high-level milestones. At the lowest level, the detailed schedule lays out the logically sequenced day-to-day effort to reach program milestones. Ideally, one schedule serves as the summary, intermediate, and detailed schedule by simply rolling up lower levels of effort into summary activities or higher-level work breakdown structure (WBS) elements.
The program or project team should develop the schedules and, in doing so, include the program manager, schedulers, and subject matter experts or managers responsible for specific areas of work. Managers responsible for resources should approve the areas of a schedule they are committed to support. If the schedule is not planned in sufficient detail or collaboratively by team members and stakeholders, then opportunities for process improvement (for example, identifying redundant activities), what-if analysis, and risk mitigation will be missed. Moreover, activity owners responsible for managing the day-to-day effort and the most experienced team members who perform the work are the best source of resource estimates. Activity owners must be able to explain the logic behind their resource estimates; if resources are without justification, management will lack confidence in the estimated durations and the schedule may falsely convey accuracy.
We recognize that different organizations may use the term “integrated master schedule” differently; for example, IMS is often used to refer solely to the prime contractor schedule. Our use of “integrated” implies the schedule’s incorporation of all activities—those of the contractor and government—necessary to complete a program.↩︎