Difference Between PERT and Gantt Chart

Table of Contents

Project management is a process of applying the skill, knowledge, tools, and techniques to complete the analyzed project activities to meet the project goals or requirements.

Project Management tools are the primary source of assistance for the individuals or project managers to analyze, prioritize, organize the tasks, or work involved in a complete project.

In the current world, project management tools provide multiple features to complete the project on time. The features are:

Providing real-time dashboards to view the project details.

Create and share project plans or details online.

Manage the tasks of a complete project.

Produce the project reports instantly.

Manage the team and its workload easily.

Out of many project management tools, PERT and Gantt charts are considered to be one among the best to visually represent and manage the tasks or activities involved in a project.

PERT vs Gantt Chart

The main difference between PERT and Gantt chart is that Gantt chart provides the exact duration of time required for the completion of each task or activity using a bar chart whereas PERT with its flow chart can determine the time duration of a complete project but not for each task.

That means to say, the Gantt chart provides accurate task duration and applicable for small projects. PERT chart predicts complete project level duration and can be used for large and complex projects.

Comparison Table Between PERT and Gantt Chart (in Tabular Form)

Parameter of Comparison	PERT	Gantt
Clarity	PERT chart will determine the accurate information of the complete project broken into activities but cannot exactly predict time frames for each activity.	Gantt chart exactly determines the time frame required for each task to get completed but when it comes to large projects, the chart will be difficult to understand.
Project Size	PERT chart will be useful for large and complex projects.	Gantt chart will be useful for small, simple and straightforward projects
Interdependency	PERT chart display networks of interdependent tasks.	Gantt chart cannot display interdependency between the tasks.
Representation	PERT chart displays project information using a flow chart or network diagram.	Gantt chart displays project details using a bar chart.
Structure	PERT chart uses boxes and arrows to display tasks or activities and their dependencies.	Gantt chart uses bars where length and position explain the start date, end date, and duration of the tasks.

What is PERT?

PERT is nothing but Program Evaluation And Review Technique. One of the best tools used for project management is the PERT chart.

PERT chart is a statistical tool used by project managers to analyze and organize the required number of tasks in a complete project, schedule the completion of each task, and coordinate each task for project completion.

PERT chart was first invented by the US Navy in the year of 1958 and it is used along with the critical path method. It was initially invented to plan and schedule complicated projects such as the Polaris submarine nuclear program by the US Navy.

A project manager can easily predict the minimum time required to complete the whole project using the PERT chart. Some of the basic steps which project managers should follow to create PERT chart are,

Firstly there is a need to analyze, find, and define all the activities or tasks involved in the whole project.

Find and include if there are any dependencies between activities or tasks.

Create arrows and nodes using the information collected through the first two steps.

Identify the time required for each task to get completed.

What is Gantt Chart?

Gantt chart is a very popular project management tool that depicts the project schedule by displaying activities against time.

Gantt chart was invented by Henry Gantt around the years 1910-1915. In this chart, activities or tasks are plotted on the vertical axis and time intervals are plotted on the horizontal axis in the graph.

In the current world, projects of all sizes use the Gantt chart for project planning which provides detailed information on what activity or task should be done on a specific day.

Gantt chart is very simple and in a single glance, we can view much information such as various activities, a timeline of each activity when it begins and when it ends, duration of each activity, the overlap of each other activities, and start and end date of the whole project.

Gantt chart software is available on both desktop and online versions. Gantt charts can be easily shared and collaborated online such that many people can be added to the project.

Main Differences Between PERT and Gantt Chart

Both PERT and Gantt charts are the best tools for project management, both have their own features and benefits for the project managers to manage a project but holds many differences between them. The main difference between PERT and Gantt is, however, Gantt chart is a bar chart with the exact prediction of time duration for each task, it can be used only in small projects whereas PERT chart determines the complete project duration with its flow diagram can be used for large and complex projects.

Gantt charts are simple and straightforward whereas PERT charts are complex network diagrams and sometimes confusing.

Gantt chart cannot visualize the interconnected tasks whereas the PERT chart can display the networks of interconnected tasks.

Gantt chart can be used for visualizing the critical path whereas the PERT chart displays the critical path of the project to project managers.

Gantt chart uses a bar chart where the length and position of the bar explain the start date, the end date of the activity, and its related duration. PERT chart uses a flow chart or network diagram that uses boxes and arrows to display the tasks and their dependencies.

Conclusion

Both project management tools have their own features and benefits to analyze, plan, schedule, and manage the project. PERT chart sometimes preferable over the Gantt chart as it explains the dependencies between the tasks but harder for interpreting large and complex projects.

Similarly, even though the Gantt chart provides sufficient information regarding the timely completion of each task but it fails to display interdependency between the tasks and critical path in a project.

Therefore, the PERT chart will be more fit during the planning phase of the project whereas the Gantt chart will be the best choice when the project is already underway so that team members will have a clear vision on their responsibilities.

References

https://pmworldlibrary.net/wp-content/uploads/2013/04/pmwj9-apr2013-weaver-where-misuse-terms-gantt-PERT-commentary.pdf

https://pdfs.semanticscholar.org/efa0/69779cfeeb1e8a57f1e66359ac72abc0ca6e.pdf

https://journals.aom.org/doi/abs/10.5465/254602

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