What project management is good at is making the complex simple, or at least manageable. That’s done by using project management tools such as project network diagrams.

A project network diagram helps project managers simplify a complex project plan, enabling them to see the project network. It’s important to have an overview of any project, see when it starts and finishes, and quickly note all the activities and how they work together. The critical path method uses project network diagrams to achieve this.

But some might avoid project network diagrams, thinking of them as those dense schematics that depict the nodes and connections in a computer network. That would be a mistake. Project managers need tools, and the project network diagram is a great one.

Let’s start with a project network diagram definition, then we’ll dive into examples, free tools and project management software.

What Is a Network Diagram in Project Management?

A project network diagram is a visual representation of the workflow of a project. A network diagram is a project management chart that is populated with boxes noting tasks and responsibilities, and then arrows that map the schedule and the sequence that the work must be completed. Therefore, the project network diagram is a way to visually follow the progress of each phase of the project life cycle to its completion.

Project managers use a network diagram to track the project schedule network, allowing them to see the progress of each activity. Then they can share the status with the rest of the project management team. This is especially helpful for those who better understand information that is delivered visually. For those team members, project network diagrams will help with the performance of their tasks and increase the project’s productivity.

Another aspect of the network diagram is that it literally illustrates the project’s scope. That’s because the project network diagram collects all the activities, milestones and deliverables defined on the work breakdown structure of the project. The Critical Path Method (CPM) and the Program Evaluation and Review Technique (PERT) are good examples of how to use network diagrams in project management. Project managers use these methods to estimate the duration of the project and create a project schedule.

Types of Project Network Diagrams: ADM & PDM

Project network diagrams can be divided into two types, the arrow diagram method (ADM) and the precedence diagram method (PDM). The main difference between an ADM and a PDM project network diagram is the way they represent tasks and milestones.

As expected, the arrow diagramming method uses arrows to represent the project activities, with the tail of the arrow being its start and the point the finish. The length of the arrow is the duration of the activity. The arrows connect nodes or boxes that are milestone symbols of the start and finish of the activity in sequence.

In the precedence diagram method, each node or box is an activity. There are arrows, but in this case, they represent task dependencies. There are four types of task dependencies:

• Finish to start: This means an activity cannot start before its predecessor is finished.
• Start to start: Use this when two activities can begin simultaneously.
• Finish to finish: Use this when activities must finish together.
• Start to finish: Use this when one activity cannot finish until another one starts.

Project Network Diagram Examples

Here are two project network diagram examples to help you understand how they’re used in project management. They illustrate the two main types of project network diagrams. We recommend creating a work breakdown structure in both cases.

1. Critical Path Diagram

Here’s a simple project network diagram example created to identify the critical path of a project. It’s a precedence diagram, so the green letters highlight the critical path activities, while arrows indicate task dependencies.

2. PERT Chart Network Diagram

PERT charts are a type of project network diagram that represents tasks, dependencies and their start and end date. As you can see in the image below, this arrow diagramming method also identifies the critical path to estimate the project duration.

How to Make a Project Network Diagram in 3 Steps

First you need to understand the chronological order in which activities need to be executed and define the project network diagram start and end point. When you’re plotting your diagram, use arrows that go from left to right. That’s how people read in the West, and the diagram should intuitively follow that pattern.

You’ll want to make your project network diagrams as clear and easy to discern as possible. That means don’t clutter the page with arrows that cross one another. In fact, any arrows that you use for directional purposes should be straight. But the length of time that an arrow represents shouldn’t be determined by its length.

1. Create a Predecessor Table

A predecessor table is a simple table that lists the activities in one column and notes their preceding tasks in another. Here’s the predecessor table for our PERT chart network diagram example. Remember that this is a predecessor table for an arrow diagramming method, where the arrows represent activities, and nodes represent milestones.

2. Identify the Activities for Your Project Network Diagram

Before you even put pencil to paper, you need to organize your tasks. You don’t want to start making your project network diagrams and realize that you’ve left out some important activities. There’s also task dependencies, where tasks can’t start or end until another activity starts or ends. Identify these with a work breakdown structure and break the project into its phases. Then you’re ready to start designing your project network diagram and find out the critical path.

3. Make a Rough Draft of Your Diagram

On a more basic level, start your project network diagram by penciling it out first. You can then erase and move items around until you’ve designed the most effective schedule network diagram.

Once you’ve made the final design, think about the type. Different fonts can emphasize parts of the diagram and make your project network diagrams easier to read. A legend or key in the corner will also help the reader understand.

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Free Network Diagram Software Tools

There’s only one way to know if a project network diagram is for you or not: try it. Lucky for you there are a lot of free tools to make a network diagram online. We picked three of our favorite project network diagram software for you to kick the tires and take out for a ride.

1. Google Draw

Google has a tool for everything you do, so it almost goes without saying that they have network diagram software. Google Draw is completely free (you don’t even have to put in your credit card). It can help you make flowcharts, UML diagrams, entity relations, mockups and, of course, project network diagrams.

Data is stored on Google Drive, but it can also store data on Dropbox and OneDrive. Google draw can import from a variety of different file formats, and it has 27 languages and is easy to share. It’s fast and has real-time collaborative support when connected to a Google account.

On the downside, there aren’t a lot of templates and shapes to choose from to create a project network diagram. In addition to this, its features are too limited to be considered a network diagram software for project management. It can be a bit of an uphill battle to learn if you don’t have a design background. This platform is best if you want to collaborate with other Google features and only make network diagrams occasionally.

2. Dia

Dia is an open-source network diagram tool that can be used to make network diagrams. It’s fairly easy to learn and can make basic project schedule network diagrams. Dia saves XML formatted documents, which are reduced automatically to save space. It’s available for Linux, Mac and Windows.

Dia is free and makes a good entry-level option for people looking to get familiar with making project network diagrams, as well as UML diagrams and flow charts.

This network diagram software has a friendly user interface, which helps users, and is also easy and fast to install because of its small file size. However, the software doesn’t have visual appeal. It’s a bit too simple, and some have criticized it as ugly because of its black-and-white design, which could be improved with color.

3. Gliffy

While Gliffy is free, the free version is very limited. If you like it, you’ll probably want to pony up for the full version, with a subscription cost. The cost is tiered, $14.85 every three months for a single user, which can make 200 network diagrams, but none of which integrate with Google Drive. A single-user business account is $29.85 for three months, which includes unlimited diagrams, but it still won’t integrate with Google Drive. For that, you’ll need the business team package, which costs $59.88 a year. The fact that the diagrams are easy to make and collaborate with will probably help with the transition from free to paid.

Gliffy is a web-based app and not suited if you’re looking to make more technical diagrams. However, it’s a free network diagram software which is a good first step into network diagramming.

Advantages and Limitations of Project Network Diagrams

Now that you know what a project schedule network diagram is, let’s take a more critical look at the pros and cons of network diagramming in project management.

Pros of Project Network Diagrams

Starting with the pros, network diagrams are a boon to project planning. The technique collects all the necessary tasks that are needed to complete the project successfully. This attention to detail before starting a project will help identify the critical path activities and where float, or the time a task can be delayed, might exist.

Making a project network diagram is also a great way to create a project schedule and, having all the activities laid out on one chart, makes it easier to order the material resources and equipment needed to accomplish them. This description of resources will help with cashflow and assembling the right project team.

Additionally, having the tasks on a project network diagram, and being able to see where they’re dependent on other activities, can help resolve issues as they arise during the project management life cycle.

Cons of Project Network Diagrams

There are also limitations. Making a project network diagram takes time and costs money to produce. Also, the project schedule network can be overly complex and difficult to discern visually in some cases. That defeats one of the main purposes of a project network diagram.

Of course, there can be errors when making project network diagrams or other unknown factors that can influence the data collected; all of this can make the network diagram misleading and potentially damaging to your project schedule. Using network diagram software doesn’t guarantee that the network diagram will accurately represent your project schedule if the sequences of activities are not mapped out correctly.

Some don’t believe in the necessity of a network diagram, that there are other tools that cover the same ground. For example, there is the Gantt chart, which is also a graphic representation of the project timeline with tasks, duration and dependencies. But a Gantt chart is an important project management tool that can also allocate resources, update project status and track tasks and time.

Best Practices for Project Network Diagrams

Taking advantage of the positives and avoiding the negatives of project network diagrams means you need to know what works. For example, a network diagram is a visual language, and like any communicative method, it requires using symbols that are shared and universally understood.

Diagrams Come to Life with ProjectManager

A project network diagram is a good start, but you’ll need more than a diagram to control the project management phases. Better to execute your project with a tool that offers full service. ProjectManager is a cloud-based project management software that takes workflow to the next level.

ProjectManager gives you the tools to turn your project network diagram into a full-fledged project schedule with Gantt charts that allow you to identify the critical path, assign tasks to your team members and add durations and due dates. You can avoid bottlenecks in your workflow by linking tasks that are dependent on one another. Break projects into milestones to further make large phases of the project more digestible.

There’s even a resource tool that shows which team members are under- or overallocated to keep the workload balanced. This keeps work flowing and prevents costly overallocation of resources or missed deadlines.

Visualize Workflows with Dynamic Boards

Workflow is further managed with the kanban project view. Just switch to the board view and everything on your Gantt is now reflected in a kanban board. The workflow is represented by customizable columns, which indicate where each task is in the project.

Each task is a card that can be dragged and dropped from column to column, which provides transparency into the process and keeps teams focused on just the tasks that they have the capacity to complete. When team members update their status, that data is instantly reflected across the entire software. Automated email notifications keep teams alert when changes are made or deadlines are approaching.

ProjectManager gives project managers and teams the tools they need to manage their workflow, know their responsibilities and stay on schedule.

After you’ve given the free network diagramming apps a spin and get a feel for how they handle, take a look at ProjectManager, a cloud-based project management software. Our online Gantt chart does much of what a network diagram can do, but also always for real-time collaboration, status reporting and it’s easy to change as the project changes. Try it free for 30 days with this trial.