John Jeffreys, in his article about pros and cons of Gannt charts brings an interesting perspective on the use of this tool in Project Management.
Let’s remind ourselves that a Gantt chart is a type of bar chart, developed by Henry Gantt, that illustrates a project schedule. Gantt charts illustrate the start and finish dates of the project tasks and summary elements.
Like John, I am convinced of the conceptual and visual value of Gantt charts. The tool encourages us to structure the project with several levels of detail, consider the dependencies between tasks, estimate their duration, identify the critical path, see at a glance the overall tasks list and progress made.
advantages of Gantt charts
- it creates a picture of complexity
- it organizes your thoughts
- it demonstrates that you know what you’re doing
- it (should) help you to set realistic time frames
- it can be highly visible
disadvantages of Gantt charts
- they can become extraordinarily complex
- the length of the bar does not indicate the amount of work
- they need to be constantly updated
- difficult to see on one sheet of paper
As any other tool, it has limitations and can lead to drifts. The most common one is to be driven or sidetracked by the software that supports it. These are often very rich and consume a lot of the most precious resource of PMs: the time available to think.
Personally, I tend to use Gantts (and I start with paper or whiteboard) as a tool to visually breakdown the project, to sequence and indicate dependencies between tasks, to review completeness of deliverables expected from the project… and, at a macro level, at the start of the project.
During the project’s life, I use detailed Gantts mainly to communicate with project teams on their tasks (contents, deliverables, estimates), to put in evidence the critical path and follow up on progress made and as importantly what remains to be done compared to the initial baseline.
Read also: John Jeffreys' blog post.