Project Critical Path and How its done in Microsoft Project
The critical path of a project is important: the time to complete all the tasks on the critical path is the time it takes to complete the project.
Project managers must focus on tasks on the critical path without loosing site of the other project tasks.
Identifying and monitoring the critical path of large projects would be time consuming and error prone without the use of project management tools such as Microsoft Project.
To illustrate the basic ideas associated with the critical path of a project we shall use a simple project detailed in table 1.
Table 1 Sample Project Task Details
|Task identifiers have been given simple names, T1, T2 etc.
||In a real project meaningful task names would be used, such as Plan Software, Debug Software, Documentation etc.
||Task durations are all in days.
||T1 does not have a predecessor, it is the first task
||The network diagram can be drawn using the task predecessors
||The finish task has zero duration, it is a milestone
Projects are undertaken by most organisations.
When a company decides to develop a new product, for example, it is a very important project, now matter how big or small the company is.
Project must be managed effectively.
Projects are broken down into tasks, which are usually broken down into sub tasks, etc.
A critical aspect of all projects is completion time: if a project finishes on time it is more likely to be in budget.
Some project tasks may be carried out at the same time as other tasks.
The critical path of a project is the sequence of tasks that take the longest to complete.
In Table 1, Task T1 is the first task on the project.
Task T1 is called the predecessor of T2.
All the tasks on the project have a predecessor, except the first.
Note that T5 has two predecessors, T4 and T8.
When all the predecessors are known it is possible to plan the project.
The project manager, usually working with other members of the project team, decides the task predecessors.
Figure 1 has been drawn using the project task predecessors.
MSP uses task predecessors to draw project network diagrams and Gantt charts.
We have used a very simple project to illustrate the critical path.
Just try one or two paths off the critical path to convince yourself.
Even in relatively small projects, involving 60 tasks say, computing the critical path manually can be time consuming and error prone.
In large projects calculating the critical path by hand can be a major undertaking.
The sample project listed in Table 1 is shown in Gantt Chart format in Figure 2, in MSP.
MSP generates the project network diagram, which is shown in figure 4.