How to create a PERT chart when starting a new project
By Indeed Editorial Team
Updated 16 September 2022 | Published 3 January 2022
Updated 16 September 2022
Published 3 January 2022
The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.
As a project manager, you may have some experience mapping the tasks of your projects or keeping track of your project's dependencies. A PERT chart is a tool that you might use to organise, schedule and map out your project's tasks. You can use a PERT chart to visualise your project's timeline and break down each task, ranging from your project's start date to its end date. In this article, we discuss how to create a PERT chart, the differences between a PERT chart vs a Gantt chart, the benefits and PERT chart terminology.
Related: How to become a project manager
How to create a PERT chart
You can use the following steps if you want to learn how to create a PERT chart:
1. Identify the project tasks
Identifying and collecting the project milestones and information is the first step in creating a successful PERT chart. You can then break these milestones into individual tasks. Early project planning allows you to prepare and define any dependencies and determine the best functions throughout the next phases.
2. Define any task dependencies
A task dependency is a milestone or task that you can finish before starting this new task. You can refer to this as a logical relationship, which establishes an existing dependency and reliance on two elements of your project. You can track your work, complete tasks and maintain clear communication by creating project dependencies. You can plan your project's timeline and duration ahead of time if the project is more complex and visualise your project's dependencies in a PERT diagram by numbering and connecting your tasks. This can help you display a visualisation of your project's tasks and the work.
3. Connect the project tasks
When you create your tasks, you can create your PERT chart by connecting all of your project's tasks. These connections can comprise nodes representing your project's milestones or events and arrows conveying your project's tasks. For example, you can place a parent event within a node, which you can visualise using squares or circles, and then draw a task arrow representing your dependency you can use to complete the event. This is a simple project structure that any project stakeholder can understand.
4. Estimate the project time frame
The next step is to estimate the overall time frame of your project by using the PERT formula and the critical path method. A critical path is a long sequence of tasks to complete, accomplishing your project. The aim is to determine the longest sequence that can take the most time to finish to estimate the shortest project duration. You can calculate a time estimate using the following details:
optimistic time: minimum time to accomplish a task
pessimistic time: maximum time to accomplish a task
most likely time: an estimate of the time to accomplish a task
To calculate the expected duration of your task and completion time, you can use the PERT formula:
(O + (4 x M) + P) / 6
You can measure the PERT formula by minutes, hours, days or weeks. For example, if you come up with 30 minutes for the optimistic time, 60 minutes for the pessimistic time, and 45 minutes for the most likely time, you can use the PERT formula as (30min + (4 x 45min) + 60min) / 6 = 45 minutes. Once you calculate the time that you expect to complete each task, you can add each estimate of your critical path to get a project timeline.
5. Manage the task progress
Managing your task progress is the final stage of creating a PERT chart. You can do this by closing your dependencies and mitigating issues until you complete all tasks. As changes occur, you can update your PERT chart throughout your project. You can pair this with a change control process, which can help you map and communicate any changes to the project. When you complete the tasks in your project, you can archive all the materials in a space that you share with everyone who can refer to it in the future.
PERT chart vs Gantt chart
Both PERT charts and Gantt charts are tools you can use to help you visualise your project from its start to end, along with all the tasks associated with the project. How each chart presents the project data is the difference:
This chart displays the project tasks and timelines linearly as a bar chart, which makes it simple to see when you can expect to finish each task. The chart's x-axis represents the time, and the y-axis displays the individual functions of the project. It's great for efficiency improvement and optimising time management, and you can adjust the tasks in a Gantt chart as your project progresses to completion. A Gantt chart is excellent for helping visualise the order of the functions and the responsibilities of the teams and individuals for every task.
A Gantt chart provides the team members and any stakeholders with project transparency by displaying a clear representation of both your project's tasks and timelines. Using a Gantt chart, you can identify if your project is on schedule and know its status during your project's lifecycle.
A PERT chart displays all of your project's tasks within separate boxes and connects each box with arrows to show a task dependency. You can structure this as a flowchart. Each box in a PERT chart identifies the time to complete each project task. You can use a PERT chart to help you manage any large, complex project and to help define all of a project's tasks and activities and develop a realistic project completion timeframe. A PERT chart is also helpful in scheduling and coordinating your team members to complete the project's tasks.
A PERT chart has the advantage during the planning phase of your project by summarising the project's tasks, dependencies, and completion date estimate. This chart can give an excellent visualisation of the relationship between tasks because of its flow chart style layout, with every task pointing to the next task.
Benefits of using a PERT chart in project management
PERT charts provide you with an insight into your project's trajectory and timeline and allow you to see any potential constraints, bottlenecks, and opportunities to increase efficiency. The advantages of using a PERT chart in project management include:
Expect and address delays: You can quickly identify where your tasks may back up if a task falls behind or fails when you have every detail of your project in terms of task time and dependencies in a diagram.
Notice opportunities for tasks to work in parallel: Before one task can begin, wait for another task to finish. You can work on some tasks parallel to each other when you assign them to enough team members and shorten your project's timeline.
Speculate tasks along the critical path: You can determine the timescale of your project by identifying its critical path. The critical path is the series of tasks with dependencies that take the longest amount of time to finish.
Plan for large, complex projects: You can assign and prioritise your project's tasks to optimise work efficiency by creating a map at the beginning of your project. This can help your team keep track of every task when your project becomes large and contains multiple interdependencies across multiple groups.
Enable a what-if analysis: When you map out your project, you can use what-if analysis to determine any outcomes that may result from any changes to the project's tasks. This analysis can help you identify any problems and places to increase efficiency.
Effectively coordinate departments: A PERT chart shows a visualisation of the role of every department that you involve in the project when you break your project down by its tasks. This can allow these teams to work together effectively to understand how their tasks depend on each other.
Related: What is critical path analysis?
PERT chart terminology
Here is a list of common PERT chart terminology:
PERT chart: A PERT chart visualises the flow of a project's dependent tasks and other events by using notations and symbols of program evaluation.
PERT event: A place in a PERT chart that represents the start or completion of one or more tasks. This task can't take place until you complete all activities that lead to the event.
Predecessor event: An event that precedes another project event with no intervention from any other event.
Successor event: An event that follows another event with no intervention from any other event.
Critical path: The path between your project's first and last event, including tasks and durations, that has the longest duration.
Critical path activity: The tasks to start and finish so you can complete your project on schedule.
Crashing critical path: Adding resources to your project to complete its activities and compress the project's schedule.
Fast-tracking: Use this method when completing activities sequentially but performing them simultaneously to save time.
Lag time: This is a delay between project tasks that have dependencies.
Lead time: The time it takes to complete a task or group of tasks.
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