Companies handling multiple projects usually have problems allocating their limited financial resources due to the fact that some jobs require highly skilled employees or specialized machinery. Scheduling the company’s limited resources such as labour, machinery, and equipment is considered to be especially difficult for manufacturing companies that are producing multiple products or construction companies with multiple projects. However, in order to minimize potential increases in operating costs, company managers can make use of various schedule development tools such as critical path, PERT, gantt charts, and critical chain scheduling. These are usually easily made due to the availability of the schedule development tools in current computer softwares.
Critical Path
Some segments of company projects can be simultaneously worked on in order to minimize the amount of time between the project’s start and finish (Gray and Larson, 2011, p.179). The reason for this is that the critical path tool allows other segments of the company project to be worked on while the schedule for the critical activities are strictly implemented (Gray and Larson, 2011, p.179). The reason for this is that some companies prefer to finish these projects at the fastest possible period of time in order to be paid earlier. The example on figure 1 revealed that implementing the critical path will only take 23 days with the most critical tasks as task 1, 3, and task 4. The reason for this is that task 2 and task 3 can be worked on simultaneously since task 2 takes 14 days while task 3 takes 16 days. The advantage of a 2 day lag on task 2 is that the company manager can schedule the labor and machinery along with task 3. The labor and machinery used under task 2 can be scheduled immediately to another project after the task 2 activity in order to minimize scheduling problems in other projects. This means that the company will be able to maximize their investment in the labor and machinery while minimizing additional costs due to the occurrence of slack time in each project.
Figure 1. Example of a critical path
PERT
The value of using PERT is that it reviews not only the project activities but its inherent risks. The purpose of PERT is that it details the cost of each project activity along with the risk of scheduling delays but on a macro perspective (Gray and Larson, 2011, p.219). The reason for this is that the tool focuses on potential causes for project delays based on an optimistic and pessimistic perception of achieving the project’s critical path. The use of the pessimistic perception means that company management may extend the time allotted for each project activity in order to prevent additional costs due to delays, which can result to the use of contingency funds as well as additional time and resources (Gray and Larson, 2001, p.219).
Figure 2. Example of a PERT chart with start and finish dates for each activity/task
Gantt Chart
The gantt chart is considered by Gray and Larson (2011, p.174) to be one of the most easily understood schedule development tool due to the use of bars to represent the time schedules of the company’s resources. This is usually used during the plannig, scheduling and status reporting segment of the company project (Gray and Larson, 2011, p.174). As seen in figure 3 below, the company’s resource activities and project time schedule are represented by a series of bars. These bars are based not only on the activity duration (Gray and Larson, 2011, p.174) but also the resources that are used. The gantt chart also reveals slack times that can occur during the project, which means that the company manager can maximize the use of labour and equipment by scheduling these resources to another project during the initial project’s slack times. This results to the maximization of limited resources while minimizing potential project scheduling delays in two company projects.
Figure 3. Example of a project using a gantt chart
Critical Chain Scheduling
The critical chain approach primarily considers the slack time of projects especially with the limited resources of a company (Gray and Larson, 2011, p.295). The company manager adds additional slack time to the activities within the project, which lengthens the scheduled date of completion (Gray and Larson, 2011, p.295). The purpose of the additional slack time is to cover potential delay problems that can affect the critical path activities such as technical dependencies instead of resource limitations (Gray and Larson, 2011, p.295). The addition of slack time is considered to be a safety measure to prevent potential project delays but can also be considered as an improvement to the performance of the project manager especially when the project is completed ahead of schedule (Gray and Larson, 2011, p.296). Figure 4 reveals that the project can be easily finished in 28 days using the critical path method but the use of the additional buffer extended the project period to 38 days.
Figure 4. Example of a critical chain schedule
References
Gray, C. F., & Larson, E. W. (2011). Project management: The managerial process (5th ed.) McGraw-Hill.
