What is a Gantt chart?
In short, a Gantt chart shows all activities (tasks and milestones) displayed against time. Typically, the list of activities is on the left hand side as a vertical nested tree of rows. This is what we call the work-breakdown structure (WBS). Horizontally, there is a suitable time scale. Each activity is represented by a horizontal bar; the position of the bar reflect the start and end dates of the activity, the length of the bar represents the duration of the activity. This allows you to see at a glance:
- What activities the project consists of
- When each activity begins and ends
- What the dependencies between activities are
- Where activities overlap with other activities, and by how much
Hence, a Gantt chart shows what needs to be done (the work-breakdown structure) and when (the schedule). PQForce is built upon the same definition when it comes to project planning. Why is that?
The key advantages of Gantt charts
There are some key advantages to Gantt charts that contribute to its importance in the planning process.
- Have a common overview: Where there is a visual framework for the work to be done, there are fewer chances for misunderstanding, especially when it comes to highly complex projects with a considerable amount of activities. Using Gantt charts allow all types of stakeholders to have the same information, set mutually understood expectations, and conduct their efforts according to the desired protocol.
- Keep track of project progress: Gantt charts were created to keep all project responsibles on track, providing a visual timeline for starting and finishing specific tasks. By giving a visual overview of tasks and milestones, these charts are meant to offer a more understandable and memorable method of maintaining timescale-based tasks and deliverables.
- Understand task dependencies: Gantt charts can make it clear how various tasks are interrelated and perhaps rely on the completion of others to meet specific objectives. These task dependencies revolve around understanding the timing of each task, which then impacts other tasks listed. This can better assure the optimum work flow, maximized productivity and overall project success.
- Get control of the future: While people easily get caught up in day-to-day tasks as detailed on a chart, an advantage of a Gantt chart is helping decision-makers look farther ahead to ensure each given project is working towards achieving the organization’s long-term strategic objectives.
Limitations and inappropriateness of Gantt charts
A Gantt chart is not designed to be the panacea for an organization’s project planning issues. There are some situations where other tools may indeed be more appropriate and effective.
- Allocating resources to tasks: A Gantt chart might not be the right tool to assign resources to activities. In a simple situation, where each task can be done by one person alone, a Gantt chart might still do. However, especially in large projects, tasks might need several resources to be done. This could be several engineers with different skills that work together on a common task and that need some materials and tools to work with in order to complete the task. However, a Gantt chart alone, in a narrower sense, does not provide the notion of resources allocation for such a scenario. In a future post in this blog, we are going to have a look at how PQForce handles this more complex situation.
- Plan with agile methodologies: Scrum, e.g., deals with rather short periods of time (e.g. a two-week sprint), during which there is also a large amount of flexibility on what tasks should be performed in what order by whom. Planning such sprint backlogs with a Gantt chart might definitely be an overkill. Especially if you intend to model each task within a sprint as a separate bar in the chart. There are better tools for doing that. Gantt charts are most appropriate for projects that are run, e.g., with a waterfall methodology or a stage-gate process where tasks have a duration of several days to weeks. Large projects are typically structured this way on a higher level. On a lower level, some tasks might be considered sprints and run in an agile way. So, if done carefully, a Gantt chart might well combine with a tool for modelling sprint backlogs.
Overall, however, the advantages of Gantt charts have been realized by all types of organizations for various kind of applications over the last decades. And it's by the very fact that Gantt charts are so appropriate to plan a project, that when you ask a project manager to show you their project plan, they will most certainly (and proudly) show you a Gantt chart.