Best Practice 2: Sequencing All Activities

Best Practice 2: The schedule should be planned so that critical program dates can be met. To do this, activities must be logically sequenced and linked—that is, listed in the order in which they are to be carried out and joined with logic. In particular, a predecessor activity must start or finish before its successor. Date constraints and lags should be minimized and justified. This helps ensure that the interdependence of activities that collectively lead to the completion of activities or milestones can be established and used to guide work and measure progress.

Once established, a schedule network can forecast reliably—in light of the best information available at that point in time—the start and finish dates of future activities and key events based on the status of completed and in-progress activities. Dates are forecast with some realism by planning work effort in sequences of activities that logically relate portions of effort to one another. The schedule network is a model of all ongoing and future effort related to the program; it establishes not only the order of activities that must be accomplished but also the earliest and latest dates on which those activities can be started and finished to complete the program on time.

The purpose of sequencing activities is to develop a networked schedule that is a predictive model of how it is intended that the program be executed. By establishing the network logic, the schedule can predict the effect on the program’s planned finish date of, among other things, misallocated resources, delayed activities, external events, scope changes, unrealistic deadlines, and the effect of risk events.

The ability of a schedule to forecast the start and finish dates of activities and key events reliably is directly related to the complexity and completeness of the schedule network. The reliability of the schedule is in turn related to management’s ability to use the schedule to direct the assignment of resources and perform the correct sequence of activities. Activities are related through different types of sequential and parallel predecessor and successor logic.

The more complex a program is, the more complex the schedule may become. However, it is essential that the schedule be as straightforward as possible so that management has a clear indication of the path forward and the necessary resources needed to accomplish activities on time. Convoluted logic techniques such as date constraints, lags, and misused logic links should be eliminated. If they are used, they should be employed judiciously and justified in the schedule’s documentation.

Once all dependencies are accounted for, the schedule should be presented for the review and approval of management and the persons responsible for performing the work. Major handoffs between groups should be discussed and agreed on to ensure that the schedule correctly models what they expect to happen. This will help everyone see the big picture needed to complete the entire program.