Keep IT projects on schedule–part three

by | Feb/9/2011

A PERT chart will show which steps in an IT project cannot be delayed without delaying the entire project.

The last two blog entries were about IT professionals creating a simple Work Breakdown Structure and a calendar representation called a Gantt chart. The whole point of project management is to help IT keep projects on track. Just as important, if the project experiences a delay, IT will be able to give you an updated project completion date.

In this case, a diagram is worth a thousand words so please look at these examples:

The simplest form of a PERT chart is circles for each step, with the name of the step and the estimated duration. Draw arrows that connect the paths related to dependencies such as:

  • This step must finish prior to the next step starting
  • This step can start at the same time as another step
  • Both of these steps must complete before the next step starts

For example:
Pert Chart

The most useful part, to me anyway, of a PERT chart is that you can identify the critical path. To find the critical path, first identify how many paths you can take from the start to the finish. Then, for each path, add up the duration of the steps. If there are 4 paths, you may end up with durations of, for example:

  • Path 1 duration: 12 days (Task 1’s duration plus task 3’s duration)
  • Path 2 duration: 11 days (Task 2’s plus Task 3’ durations)
  • Path 3 duration: 10 days (Task 4’s duration)

In this case, path 1 is the critical path because if there is any delay at all in path 1, the entire project will be delayed. The other paths contain slack time so they can experience delays if necessary.

Be sure to read my two most recent blog entries about the Work Breakdown Structure and the Gantt chart.

Please post your comments on this blog.