Gantt Charts

Source: Envision Software: Gantt Chart Tutorial

Project Timeline Management - Gant Chart

What is a Gantt chart?

A Gantt chart is an excellent tool in the hands of project managers who wish to visualize, schedule, and track scheduled and actual progress of projects. Its graphical nature allows executives and non-managers to readily understand project flow, without a requiring a complete tutorial in project management.

Every time we, in our project management careers, go through the rigmarole of our projects, trying to meet and beat our own-set goals, a silent word of gratitude goes to the heavens for Henry Gantt for conceiving this intuitive diagram for charting project timelines, for the Gannt Diagram allows us to excel in this chosen career.



Henry Gantt (1861-1919), a mechanical engineer, management consultant, and industrial advisor developed Gantt charts in the 1910's. Not as commonplace as they are today, Gantt charts were innovative and new during the 1920's, where Gant charts were used on large construction projects like the Hoover Dam started in 1931 and the Eisenhower National Defense Interstate Highway System started in 1956.

Now, a staple project management tool and buzzword in the repertoire of modern project management tools today, Gant charts are routinely deployed in the by project managers, planners, and system developers. Working on projects without them is unthinkable, except in the rare case when the inherently nature of the work does not require them.

The Gantt chart has attained world renown, known in Spanish as carta Gantt (Gannt Chart), grafica / graficas de Gantt (Gantt Graphic), and diagrama / diagramas de Gantt (Gant Diagram) and in French as diagramme de Gantt (Gaant Diagram), indeed the whole world speaks this common language of project representation.

Henry L. Gantt's global contribution to the modern project management is honored today through the The Henry Laurence Gantt Medal. This medal, established in 1929, is awarded for distinguished achievement in management and service to the community.
Practical Application

So, how does someone use a Gannt chart? These charts are generally introduced during the planning and scheduling stage of projects. A visual tool, the charts allow us to obtain a bird's eye view of the project in its totality. From beginning to the end, the charts force us to:

1. Make a realistic assessment of the end-time of the project.
2. Sequence our tasks (or phases, or activities) - one after the other, as well as in parallel.
3. Think in terms of task dependencies - which task is dependent on what.
4. Concentrate on the necessary resources, both when and where, throughout the run of the project.

Once the Gantt charts are drawn up, and project execution begins, we start comparing our actual, ground-level performance against what was planned. This comparison is possible by checking the field reports against the Gantt charts. Thus, we get to benefit from them in two immediate ways:

1. To monitor work in progress. At the minimum, a percentage of completion can be worked out, by taking a snapshot of the progress "right-now", and comparing it with the chart, for the "right-now" point of time. If there are any slip-ups in terms of time or cost, we are forced to question our optimism (or hope?) that the tasks would get completed earlier then they actually did, at the planning stage. This introspection helps in more realistic planning for a now more matured manager in their future projects.
2. To also think in terms of speeding up future tasks, while there is still time, to redeem the total project's deadline. Perhaps resources (better manpower, more funds, or additional material) need to be allocated much in advance for a task that is going to be initiated later down the line? Perhaps some tasks may be rescheduled in a more efficient manner, in order to meet some unforeseen contingencies that have occurred after the project started?

Additional Resources

How to make a Gantt chart

A Gant chart, after all this hoopla, is just a chart with rows and columns. One simply writes all the tasks, one below the other, so that each task occupies a single row. Alongside the names are columns drawn, to indicate the dates that may be in increments of days, weeks or months. Depending on the total length of the project, we may decide on which granularity of the date is comfortable for us - days, weeks or months.

Now, for each task in a row, we draw a horizontal (preferably hollow) bar alongside, with its start point in the column representing the date when it is scheduled to begin, and the end point in the column of the date when it is expected to end. Once these horizontal bars are drawn, we step back and get to observe the tasks that are going to run sequentially, in parallel, or overlap.

After the project has commenced, managers simply fill in the hollow bars to a length that is in proportion to the fraction of the work that has been completed, for every task. In order to judge where we stand on any given date - say today, we can draw an imaginary vertical line through the chart at the current date - this is a "snapshot line". The tasks that are supposed to have completed fully shall be to the left of this snapshot line. If they are indeed completed, their hollow bars shall have been completely filled. Partial filling indicates slip-ups. Tasks that are crossing the snapshot line are current tasks in hand; well, at the least they are tasks that were scheduled to have begun before today. If the horizontal bar on such tasks is filled in to the left of the line, then the current tasks are behind schedule; if they are filled in to the right of the line, then they are ahead of schedule. Future tasks, of course, will lie completely on the right of the snapshot line.
Complex projects

What has been described above is for simple projects. Ideally, tasks in simple projects would not go beyond a single page, which makes them manageable. Often, and especially in complex projects, each task may be broken into smaller and more easily manageable subtasks. These subtasks may be moved to subordinate charts, with their own timelines. In management terminology, the process - of breaking up of these tasks into independent unit-tasks that can be completed on their own - has been given an exotic name of WBS, or "Work Breakdown Structure". This process enables the manager's mind to grasp the project in its entirety as well as to think in terms of allocating resources, assign responsibilities, and measure and control the project, for every task and sub-task.

Further, in team-oriented projects, where each task is to be handled by different personnel, there might be an additional column against each task, where initials of these personnel may be entered, to identify who is supposed to be doing what.
Project Milestones

Achieving milestones are occasions for celebration, to pop the champagne. They help to boost the morale of personnel involved in making the project a success. If the Gantt chart is drawn up along with suitable (and achievable!) milestones, by using some special symbol such as brightly-colored diamonds, and the chart is kept in some centrally visible place, it would motivate all the people to achieve them. These milestones could range from perhaps the approval of p roject design by the customer, or completion of project prototype, to delivery of individual modules by different teams.


After Henry Gantt showed the way, quite a wealth of management literature has evolved on how to manage projects. Indeed, Project Management is a full-fledged discipline in itself, deserving of a separate academic degree for those who pursue it as a career and profession. More powerful models have evolved in the past few decades, which strive to capture the complexity of human endeavor and track and monitor its progress. The Gantt chart continues to be used in some avatar or the other in all such models. And for simple projects, Gantt chart is the solution.
Addendum: Gantt Spelling

Widely discussed, but difficult to spell, and far more than a buzzword, Gantt's unusual surname gives rise to much dismay as people search for information on Gant Charts, Gantt Charts, and Gannt Charts. As such, I have included these common misspellings so that when your boss tells you to create a Gant Chart, Gant Chart, or Gannt Chart - this resource will be readily located, and your life as a project manager can soar to new heights.

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