the resources to move the work forward efficiently. Commitments are made at these meetings, and based upon commitments, plans are developed.
The typical driver for planning is the project network schedule that shows critical and subcritical activities that must be accomplished during the ensuing week so that the project will not be delayed. Trade supervisors are expected to commit to working on the critical activities, since, if these activities are delayed, the project will be delayed. On a schedule-driven project, other considerations required to complete the activity, such as adequate labor, resources, and equipment, become secondary. The critical path network scheduling method leads managers to conclude that work must be performed as a first priority, on those activities that are on the critical path.
Unfortunately, since the other considerations noted above do most certainly have an impact on completing activities, at the next coordination meeting, it is revealed that many of the planned activities are not completed. Based on the fact that planning is, on average, about 50% reliable, if each task is reviewed to determine whether it was completed or not, the result would be that about half the activities were not completed. The conclusion is that it is important to consider all of the factors that will affect activity completion, not just whether the activity is on the critical path, when developing the weekly production plan.
The Last Planner Process© suggests considering four criteria before making the commitment to place an activity on the short interval plan. The four criteria are:
Definition says that the work is well enough described that it can be assigned and the completion of the activity will be well defined. For example, when reviewing planning success at the end of the period, if the sheet metal contractor had listed an activity to complete installation of ductwork in 10 specific rooms, but only 9 rooms were completed, or if 10 rooms were completed but they were not the 10 specified, that activity would have not been completed successfully.
Soundness means that all resources required to complete the activity will be available when execution of the activity takes place. This includes physical resources, such as materials and tools, as well as nonphysical resources, like information, and space.
Sequence focuses on the physical requirement to complete certain tasks prior to other tasks. In the event that several activities could take place at the same time, proper sequencing means that the choice among those activities available is the best one to move the project toward achieving its goals.
Size means that the correct amount of work is assigned so that the crew can complete it with a standard level of effort. Too much work assigned will stress the crew and begin to impact safety and quality, as well as raising the risk that all the