Project Scheduling Models
There are various methods for scheduling projects. Here we will look at two simple project scheduling models – Gantt charting and the Program Evaluation and Review Technique (PERT). Both are schematic models, but PERT also has some mathematical model adaptations.
A Gantt chart is a bar chart that shows the relationship of activities over time. Table 7.1 gives the symbols often used in a Gantt chart. An open bracket indicates the scheduled start of the activity, and a closing bracket indicates the scheduled completion. A heavy line indicates the currently completed portion of the activity. A caret at the top of the chart indicates current time.
TABLE 7.1 Gantt chart symbols
|[||Start of an activity|
|]||End of an activity|
|[-]||Actual progress of the activity|
|v||Point in time where the project is now|
Figure 7.1 shows a Gantt chart of a student preparing for final exams. Project activities are listed down the page and time across the page. The project activities are studying for exams in English, History, Math and Psychology. Math is broken into two sub activities – studying concepts new since the last exam and studying concepts covered on previous exams, for review. By examining the horizontal time axis, we see that all activities must be completed in three and one-half weeks.
Studying English, for example, is scheduled to start at the beginning of week 1 and end after one and one-half weeks. The caret at the top indicates that one and has already been done. Students can use this chart to visualize their progress and to adjust their study activities. As you can see, one of the strength of project scheduling with Gantt charts is the simplicity of the schematic model.
|Study concepts new since last exam||[——-||]|
|Study concepts new since last exam||[ ]|
|Study Psychology||[ ]|
Figure 7.1: Gantt chart for Project Scheduling