The Gantt Chart
The Gantt Chart is one of the most common tools used in Project Management. Perhaps one reason for this is that it is the default view in software tools such as Microsoft Project.
However, the Gantt chart is just one of many project management tools. Take a look at my previous blog on the 14 Tools of Project Management to investigate some of the other tools.
I believe that some of the problems with Project Management are people using a Gantt Chart when another tool is more appropriate.
What is a Gantt Chart
A Gantt chart (named after Henry Gantt) usually show a list of tasks vertically, against a time based axis horizontally. The schedule for each task is then highlighted against its starting and end dates. It is usual (but not necessary) to arrange the tasks down the left side in sequence. This will normally give a Gantt chart a general top-left to bottom-right appearance. The following Gantt Chart example illustrates this.
Benefits of a Gantt Chart
Apparently the chart can be easily understood by most people, however, if it included everything possible it would become cluttered and difficult to read. A Gantt chart can include all of the following information:
- A list of the project tasks
- The start and end date of those tasks
- Dependencies between the tasks
- Resource Names
- Task Durations
- Costs (or other task information). It is possible to put information inside, on top of, below, to the left and to the right of a Gantt bar.
A simple Gantt chart can soon become cluttered with all of this extra information.
Disadvantages of a Gantt Chart
There are many problems with a Gantt chart. Firstly, there is vital project management information that is not shown by default. If all that is being used to manage the project is a Gantt chart, then the project could be at risk. Here is a list of things NOT shown explicitly in a Gantt Chart.
- The Project Objectives: Vital for any successful prject
- Task Priorities: Which tasks are the most or least important (or difficult)
- Task Work Content: Remember that Work and Duration are not the same thing. The Gantt chart concentrates on durations.
- Task Risks: By default the Gantt chart gives no indication of risks. A Risk Log should be used for that purpose.
- Stakeholder and Communication: Projects fail because of problems with people (stakeholders) and communication.
These are key project management items that should never be forgotten.
There are other items that can lead to confusion in a Gantt chart:
- Adding too much detail. Too many tasks or too much detail.
- Tasks that are too long or too short for the chosen timescale
- Adding repeating tasks such as meetings. This is possible, but removes dependencies.
- Missing tasks. If the task is forgotten, no project management tool will help!
- Difficult to print. Gantt charts can be difficult to print out using A4 paper, and a large format printer is often required.
- A tendency to only add the “Action” tasks and forget the “Management” tasks such as checking, communicating, testing etc.
All of the above make Gantt charts easy to use for simple projects, but difficult to use for complex projects. However, my favourite reason for not using a detailed Gantt chart is that it encourages others to be a proejct manager on your project.
If the Gantt chart show dependencies, durations, assignments etc, then it can be difficult to hold a meeting to discuss one thing, when people want to comment on the ownership, durations, or dependencies.
Using the correct Project Management tool is vital. If you want to:
- Discuss the project objectives, use the Project Charter or Specification
- Talk about the task dependencies, use a dependency chart
- Discuss the Resource allocation, use the Responsibility Assignment Matrix
- Ensure project communication is satisfactory, use a communication plan
Gantt charts have their place for simple projects, but can soon become unwieldy. I’ve spoken to project managers who employ people just to keep their Gantt Charts up-to-date!
Gantt charts can quickly become too detailed, and an ‘end to a means’ rather than being a ‘means to an end’!