Project Smart ~ Exploring trends and developments in project management today

Calendar iconNot recorded
Adobe PDF icon

Gantt Charts, PERT Charts: What Use Are They?

~ By Linda Russell

Gantt chart

Gantt charts and PERT charts are useful tools for visualising and communicating information about projects, but they have a number of limitations. In addition, the ease with which they can be created using software applications makes them open to misuse and misinterpretation.

Project Breakdown

Part of the problem is that there isn't a clear understanding of how to break the project down in the first place, and using Gantt chart software to do this isn't necessarily the best way of going about it.

A common method of breaking a project down is using a Work Breakdown Structure (WBS). This concentrates on analysing the scope of the project according to its outcomes or deliverables. This method of breakdown does not necessarily imply any dependencies (logic) or sequence, hence neither the Gantt chart nor the PERT chart are suitable tools for carrying out this analysis.

Project Management Methodologies such as PRINCE2 also seek to analyse the project in terms of deliverables, "Products," although there is more of a sequence involved in the definition of the stages: in particular, there is a process of sign-off for each stage, sometimes called "Gateways", before the project is allowed to move on to the next.

Using the Charts

Having defined the breakdown, you should have a list of tasks which need to be completed in order to produce the desired outcomes. These tasks will have dependencies and durations and hence can be scheduled. Now's the time for the PERT or network chart software to be used. You can concentrate on the logic of the task relationships: the software should do the scheduling for you, including calculating the critical path.

Once the logic has been defined and the schedule has been calculated, the result can be displayed on the Gantt chart. It's often best not to show the dependencies (links) on this chart, especially if there are a large number of tasks and complex dependencies between them. It's also helpful if you can produce separate Gantt Charts for different WBS levels or stages/products, as they will have fewer tasks in them. Summary Gantt charts showing higher levels in the WBS may also be useful.

Updating Progress

Charts should be seen as snapshots of the current project situation: they should be dynamic and change as circumstances change, particularly as work is carried out on the tasks.

I've seen a number of cases where the project manager creates a beautiful Gantt chart showing the project being completed on time, with nice neat task relationships, sends it out to all the people involved - and then they sit back and leave it at that. When asked how the project is going, they say "fine" because the chart looks fine. What they fail to do is update it with what's actually happening and re-schedule it according to real progress.

If some tasks are taking longer than expected, are they going to continue at the same pace and if so, what impact will this have on the rest of the plan? Remaining effort needs to be estimated and the project rescheduled.

What will be the effect if some tasks are ahead of schedule? The impact on resources will not be apparent from just looking at the charts: other tools are needed, such as resource histograms, to identify peaks and troughs in resource utilisation.

Conclusion

Charts and schedules are only tools to help you manage better - they won't give you the answers - and you must keep them up to date.


Linda Russell has an M.A. (with Distinction) in Technical Authorship, and over 25 years' experience in software implementation and consultancy.


Comments

Be the first to comment on this article.

Add a comment



(never displayed)



 
2000
Is it true or false that green is a number?
Notify me of new comments via email.
Remember my form inputs on this computer.

The Meat of a Business Case

Abstract word cloud for Business case with related tags and terms

Writing a business case is a crucial component in the business process. This article covers the important components in a business case.

Work Breakdown Structure Made Easy

Work Breakdown Structure

The Work Breakdown Structure is a deliverable-oriented, hierarchical decomposition of the work to be completed by a project team.

Authority Earned, Not Given

Group of business people looking and pointing at a chart

For project managers, the support of their team is critical for completing projects successfully. Yet, a team's respect cannot simply be assigned like a task.

Top 10 Steps to Successful Goals

Businessman sprinter winning a track race

Help avoid the great 'Rinse and Repeat Trap' by following these 10 steps to setting successful goals. You may have to work for it, however!

PROJECT SMART is the project management resource that helps managers at all levels improve their performance. We provide an important knowledge base for those involved in managing projects of all kinds. With weekly exclusive updates, we keep you in touch with the latest project management thinking.

WE ARE CONNECTED ~ Follow us on social media to get regular updates and opinion on what's happening in the world of project management.


Latest Comments

Pani Tararo commented on…
SMART Goals
- Sat 22 April 12:58am

Cheryl commented on…
The Role of the Project Manager
- Thu 20 April 2:36pm

Dr. Nishikant Bohra commented on…
Who is the Project Manager?
- Thu 20 April 8:00am

Latest tweets

General Project Management • Project management methods - 2 days left to have your say https://t.co/e2FveskJHB #projectsmart #pmot about 7 hours ago

General Project Management • Using Milestones to Make Projects More Manageable https://t.co/NLJlBoL8x3 #projectsmart #pmot about 1 day ago

General Project Management • 60 Second PM: 5 Tips for Improving as a Project Manager https://t.co/Ek7OiZU47P #projectsmart #pmot about 1 day ago