Explanation of the Gantt Chart

Its use a simple logic calculations to identify the critical path, it does include:

– A sequence of activities has a timing duration.

– Adding the timing durations from the start till the end (forward pass), it helps to determine the early and late start.

– Deduct the timing durations from the end to the start (backward pass), it help to determine the late and early finish.

– Deduct the early finish from the late finish, by that we found the total float.

– The early start for activity A is 0, while the late finish for activity R is equal to its late start.

The critical path is the longest serious of activities in the diagram with no flexibility, linked to each other without interruption. In other word it’s the path has activities with total float equal zero.While the duration of the project determine by the earliest and late finish of the last activity in the project.

Gantt chart is useful tool to project manager, in this chart there is a calendar time scale enable to determine the project duration including , not only the working days, but also holydays and weekend.

If the project starts on 11 January 2010 in 5 day working week, assuming there is no holidays the earliest day the project will completed is 2 April 2010. (See end of the document).

a. As activity P is a critical activity in a critical path a one day delay will create a delay in activities Q and R, which delay the project end for one day. Also it could generate an increase in project cost. The project manager should be able to predict this before it’s occurred, therefore he should analyses the network diagram and looking for maneuver margin.

b. If activity N completed 1 day earlier, it could give other activities in the path such as O, P, Q, and R one day flexibility. However it doesn’t mean that the project will finish earlier because other activity recourses were schedule and it could be not available at that time, but still there is possibility to the project to finish 1 day before than schedule.

c. Activity I is not critical activity, that’s mean it has a float or slack which is in this activity is 6 days. There for a delay for 2 days in this activity will not create a delay in whole project, however there a possibility to generate increase in cost than the estimated before.

In the network diagram all the project activities are represented accordance with the relations that exist between them, the activities represented by nodes (boxes), these mentioned the beginning and the end of each activity

The benefits for the diagram are:

• Obtain a schematic representation of the project.
• predict the required time to complete the project.
• distinguish between critical and non critical activity in the project, and thus determine the possible maneuver margin for each task, which can be by moving some resources from non-critical tasks and focus on critical activity, which contributes to reduce the time of the project with a fixed cost.

Implementing the network diagram is summarized in these steps: