Four Characteristics Of A Reliable Schedule

GAO’s research tells us that the four characteristics of a high-quality, reliable schedule are that it is comprehensive, well-constructed, credible, and controlled. A comprehensive schedule includes all activities for both the government and its contractors necessary to accomplish a program’s objectives as defined in the program’s WBS. The schedule includes the labor, materials, travel, facilities, equipment, and the like needed to do the work and depicts when those resources are needed and when they will be available. It realistically reflects how long each activity will take and allows for discrete progress measurement.

A schedule is well-constructed if all its activities are logically sequenced with the most straightforward logic possible. Unusual or complicated logic techniques are used judiciously and justified in the schedule documentation. The schedule’s critical path represents a true model of the activities that drive the program’s earliest completion date, and total float accurately depicts schedule flexibility.

A schedule is credible if it is horizontally traceable—that is, it reflects the order of events necessary to achieve aggregated products or outcomes. It is also vertically traceable: activities in varying levels of the schedule map to one another and key dates presented to management in periodic briefings are in sync with the schedule. Data about risks are used to predict a level of confidence in meeting the program’s completion date. Necessary schedule contingency and high-priority risks are identified by conducting a robust schedule risk analysis.

Finally, a schedule is controlled if trained schedulers update it regularly using actual progress and logic—based on information provided by activity owners—to realistically forecast dates for program activities. Updates to the schedule are accompanied by a schedule narrative that describes salient changes to the network. The current schedule is compared against a designated baseline schedule to measure, monitor, and report the program’s progress. The baseline schedule is accompanied by a basis document that explains the overall approach to the program, defines ground rules and assumptions, and describes the unique features of the schedule. The baseline schedule and current schedule are subjected to configuration management control. Table 7 shows how the 10 scheduling best practices can be mapped to these four characteristics.

Table 7: Best Practices Entailed in the Four Characteristics of a Reliable Schedule

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Schedule characteristic	Best practice
Comprehensive, reflecting all activities as defined in the program<92>s WBS labor, materials, travel, facilities, equipment, and the like needed to do the work and whether those resources will be available when needed how long each activity will take, allowing for discrete progress measurement with specific start and finish dates	Capturing all activities Assigning resources to all activities Establishing the durations of all activities
Well constructed, with all activities logically sequenced with predecessor and successor logic limited and justified use of unusual or complicated logic a critical path that determines the activities that drive the program<92>s earliest completion date total float that accurately reflects the schedule<92>s flexibility	Sequencing all activities Confirming that the critical path is valid Ensuring reasonable total float
Credible, reflecting the order of events necessary to achieve aggregated products or outcomes varying levels of activity, supporting activity, and subtasks a level of confidence in meeting a program<92>s completion date based on data about risks for the program necessary schedule contingency and prioritized risks based on a robust schedule risk analysis	Verifying that the schedule can be traced horizontally and vertically Conducting a schedule risk analysis
Controlled, being updated regularly by schedulers trained in critical path method scheduling statused using actual progress and logic to realistically forecast dates for program activities accompanied by a schedule narrative that describes updates to the current schedule compared against a baseline schedule to determine variances from the plan accompanied by a corresponding basis document that explains the overall approach to the program, defines assumptions, and describes unique features of the schedule subject to a configuration management control process	Updating the schedule using actual progress and logic Maintaining a baseline schedule

Source: GAO | GAO-16-89G.