What is a Gantt chart?

The Gantt chart is a project management tool. This chart visually represents the project plan.

The Gantt chart – as you might guess – gets its name from its creator – Henry Gantt. Henry Gantt is an American engineer, scientist, one of the pioneers of project management science. The chart was probably created between 1910 and 1915. Earlier, a similar tool was developed in 1896 by Polish management theorist Karol Adamiecki. He called this tool a schedule. Unfortunately, Adamiecki did not publish his tool until 1931, and in addition he published it only in Polish. Therefore, we do not have Adamiecki’s charts today, but Gantt charts.

With the help of a Gantt chart it is possible to manage projects comprehensively. Such a chart is like a set of building blocks, from which we can arrange the various elements of the project into a visual whole. On the chart we can see all the small tasks, connected by mutual dependencies. Two tasks can be completely independent, partially dependent or dependent, that is, they must occur one after the other. This is defined as follows:

• FS (finish to start) – once activity A is completed, activity B begins.
• SS (start to start) – task B can begin when task A begins.
• FF (finish to finish) – task B can only end when task A is completed.
• SF (start to finish) – task A cannot end before the start of task B (overlap).

Gantt chart – an example

When building a house, we can finish the kitchen and bathroom at the same time, but we can’t do the finishing of the kitchen and the plumbing at the same time (look at the Gantt chart example below).

If two tasks are interrelated and the first one is delayed, that is, for example, the plumber does not manage to do the plumbing in time, then the next task, that is, finishing the kitchen and bathroom, cannot be started. And if the next task can’t be started, then the whole task will be done on another date. The same will happen with any subsequent task that is related to the plumber’s work, that is, for example, the installation of household appliances.

In short, delaying the plumber will delay the finishing of the kitchen, bathroom and hold up the installation of the home appliances. When dealing with a large project, a Gantt chart is a great visualization of project logistics that can be used by a multi-person team. However, in order for the chart to show the current status of the project, the project team must update the time and percentage of completion of each task on a daily basis. With a complete picture, the project manager, together with the team, can react to current problems and take corrective action. By monitoring the project’s execution, it is also possible to optimize activities to get the project done faster.

How to prepare a Gantt chart?

We can divide the preparation of the Gantt chart into 5 basic steps. They are:

1. Breaking down the project into goals for each task.
2. Establishing the duration of the project by determining the completion times for the tasks.
3. Determining the order in which the tasks will be completed and setting start and end dates.
4. Determining where the tasks will be completed and the responsibility for their implementation.
5. Developing in graphic form all the activities performed.

The task completion time is represented on the Gantt chart in the form of a rectangle, which is placed on a linear scale. Its left edge corresponds to the beginning of the task, and its right edge corresponds to its completion.

The advantage of this tool is the ability to monitor and coordinate multiple tasks and people. It helps optimize the use of all resources and the scheduling and timely execution of individual tasks.

Methods of project visualization

Stacked bar chart

One example of a Gantt chart is a bar chart (such as the example above). This chart usually consists of a timeline and a list of tasks to be completed, which is placed on its left side. Such a task list also specifies the start and end date of the task. It is also a good practice to have detailed information about the days allocated for the completion of each task, cost data and the current degree (in percent) of progress on each task.

Cascade chart

The Gantt chart in the cascade model is used to guide projects. This model assumes that the project task is divided into sequences of steps that must be fully completed within a certain time.

A project consists of tasks, and each task is a cascade (staircase). Tasks, on the other hand, are made up of activities, and similarly, each activity is also a cascade (staircase). Each task or activity of a project presupposes the completion of the preceding tasks or activities.

The cascade model is preferred by teams that focus on execution processes (such as construction or manufacturing). This model is less commonly used for conceptual projects, where it is more difficult to predict next steps. Cascading Gantt charts define the project schedule, organizing it by the start and end dates of individual activities and tasks.

The Gantt chart also defines project milestones – i.e., goals that project teams should achieve by a certain date. Milestones on Gantt charts are optional, but recommended.

Sprints

The Gantt chart can also show the dynamic changes that are made in projects based on the Agile method. According to this method, projects are divided into small iterations, called sprints. When one sprint is over, the tasks completed during it and any changes made are the basis for planning the next sprint. Changes after individual sprints can be presented in Gantt charts.

Gantt chart software

There are many Gantt chart programs available on the market. For example, these are: Asana, Trello, Basecamp, TeamWork Projects Software, Fortask, FlexiProject, Firmao. These programs offer features such as schedules, tools for combining tasks, resources for processing project data and illustrating how different options affect completion dates. However, it is not necessary. If the project is not complicated and does not have too many tasks, we can do it in Excel.

Where to use a Gantt chart?

Gantt chart is a very important tool for project management in all industries. With a Gantt chart, we define tasks, their start and end dates. Then we define the interrelationships of tasks, determining which tasks are dependent and which can happen in parallel. The method is used to monitor projects in which there are many tasks, so a multi-person project team have to work on them. The project manager, thanks to the chart, has a complete picture of the situation.