The Gantt chart is arguably the most popular tool used by project managers for project management. Its application is particularly useful in the scheduling phase of the project, when deciding on the flow of the tasks is critical. The Gantt chart was first introduced by a United States engineering professional named Henry Laurence Gantt during the 1910s, although similar charting methods were employed by a Polish steelworks expert named Karol Adamiecki during the 1890s. The Gantt chart we know and use today was nevertheless named after Henry Gantt, and has been used continuously by project managers since its inception. Medium-sized projects, as well as monumental projects such as the construction of the Hoover Dam – all enjoyed the benefits brought by the Gantt chart.
A Gantt chart is basically a bar or a line chart oriented horizontally. The vertical axis is used for the list of tasks, while the horizontal axis represents the timeline. At the very top of the Gantt chart are divisions of time; the length of which is the project’s estimated duration. At the left part of the Gantt chart, tasks are listed down to occupy one row each. Adjacent to these bars, just under the timeline are the actual schedules, represented by either bars or lines. The positions of these bars or lines correspond to the planned start and end dates for this task. Critical paths and interdependencies may be represented by lines, and all parts may be color-coded according to different criteria.
When and when not to use a Gantt chart
When a project calls for precise scheduling, then it calls for a Gantt chart. A Gantt chart can help you analyze the flow of the tasks in a project, since it provides you a display of more or less the entire project. Gantt charts are very useful in large projects in the sense that it allows you to spot any possible problems during the project. This, in turn, allows you to correct the problem before it occurs. Some, more complex Gantt charts will also help you make sure that a task does not use up the resources allotted for another task. Probably the most important benefit of the Gantt chart is that you will be able to visualize the dependencies between tasks, ensuring that the project runs smoothly. For instance, if a number of tasks are dependent on the completion of a prerequisite task, then you can focus on the prerequisite task in the meantime. This is because delaying the prerequisite task creates a domino effect – all other tasks dependent on it will also be delayed.
Of course, not every project needs to have a Gantt chart. A Gantt chart is most effective when used for medium to large projects, when there are many tasks that need to be carefully plotted and scheduled. Small projects with only a handful of tasks often do not need to employ a Gantt chart, as it may be sufficient, and in some cases more practical to just write down everything on a piece of paper. If you can even just memorize the flow and the schedules of the tasks, then it would be better not to use Gantt charts.
While the Gantt chart shows the dependencies between tasks, it does not display the relationship between one task’s progress with another task. For cases where you need such a feature, it is often better to use other charting methods, such as a PERT chart.