What Is a Network Diagram in Project Management? (Examples Included)

Whether you’re a PM noob or a PMP, being aware of the ins and outs about network diagram project management is important. Indeed, it will guarantee that your project management skills will be of the finest vintage.

Here we’ll get into the weeds of network diagram and its place in project management, examples, making a template, and advantages and disadvantages.

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What is a project network?

A project network refers to the idea that all the activities, events and milestones in a project scope form a network. In other words, they are connected. The easiest way to think of this is through the sequence of tasks. Task A is connected to task B in a network by coming before it in a sequence.

There are also task dependencies, which networks are useful for understanding connections. They are:

Finish to start, which is the most common form
Finish to finish
Start to finish
Start to start

For example, finish to start means that you cannot begin working on a task before a previous one is complete. EG: You must finish designing the product before you can begin manufacturing it.

A network diagram is a way of implementing WBS (work breakdown structure), i.e. taking the main deliverable and breaking it down into work packages, then into individual dependent and prioritized tasks.

You can use this logic and network diagrams with many of the types of project management methodologies out there. That includes waterfall, Kanban, Scrum or even extreme project management (XPM).

What is a network diagram in project management? Our definition

Our network diagram definition is one that helps you visualize the diagram that is the network of project management. This is for all of you who’ve been asking: a network diagram is used to show what?

Now let’s get into the project management description of network diagrams. A network diagram is a wireframe that has free-floating boxes connected by lines, or in more technical terms, nodes connected by arrows.

This is different from other diagrams like a family tree or organizational chart. Network diagrams are more like flowcharts, as they show the workflow from the start of the project to its end date.

When is the use of network diagram project management appropriate?

There are many instances when it is appropriate to use a network diagram as a project management tool.

Firstly, project schedule diagrams are a vital part of planning and managing project schedules, which is useful for organizing work hours as well as for communicating expectations to stakeholders.

Similarly, network diagrams can be both predictive or deterministic in setting task and project durations.

Project management network diagrams are a necessary tool for resource allocation. When you use such a diagram, it’s easier to plan and shift both labor-power and other resources to the task-congested areas.

Next, when it comes to the logical relationships between tasks and activities, like task dependencies and interdependencies, project diagrams are the best way to organize and stay on top of these relationships.

Finally, a project management network diagram is used for setting buffers between the completion date of the project work and its official project end date.

Advantages and disadvantages of network diagram project management

There’s a good side and a bad side to everything, isn’t there? Why should a PM network diagram be any different? Let’s enumerate some of the pros and cons of network diagrams in project management.

Advantages

Here are some of the benefits to using network project diagrams.

Great visual representation

Whether for seeing how individual tasks are related, or getting a great visual overview of the entire project scope, network diagrams are ideal for any kind of project, from simple to complex projects. From stakeholders to project managers to all the team members, having a shared visual overview keeps everyone in sync.

Points out potential bottlenecks

When planning the process of your project, it’s easy to get lost in a checklist of tasks. Once you use a network diagram, however, the areas of task overload and other bottlenecks become more apparent, letting your team plan in advance on how to manage them.

Practical project scheduling

Alongside budgeting, scheduling is one of the most critical aspects of project planning. When combined with something like a Gantt chart, a project network diagram streamlines the scheduling of tasks, staff and resources.

Identifies dependencies

Having a clear conception of your task dependencies is what separates the pro project manager from the amateur. With a network project diagram which shows all the relationships, you can apply buffers, leads and lags to optimize dependency management.

Disadvantages

Now on to the drawbacks of project management network diagrams.

Overplanning

A network diagram means a lot of planning has gone into the sequence of tasks, time estimates, and resource allocation. This means that if there is any mistake in the planning, it can have far-reaching consequences for the rest of the plan.

Time consuming

As noted, creating a network diagram takes a lot of planning and therefore a lot of time, which can delay the beginning of a project or eat up a lot of your team’s hours.

Complexity

The bigger the project scope, the more complex a network diagram can appear. When there are too many interconnected nodes and arrows shooting every which way, the diagram can be hard to read and understand, which can lead to errors.

What are the different types of network diagrams for project management?

There are two network diagram types to keep in mind when implementing a project diagram: the arrow diagram method and the precedence diagramming method. ADM expresses the work on the arrows and the milestones as nodes, while PDM uses the nodes for tasks and emphasizes task relationships.

Activity on Arrow Diagram

The activity on the arrow diagram is also called the arrow diagram method, or ADM, as well as the activity network diagram.

In this visual representation, the work, the different activities and tasks are expressed by the arrows and generally include the duration of the task. The nodes are the milestones, or the beginning or completion of a task or set of tasks. It is called an i-node to mark the beginning of work, and a j-node to mark its completion.

In terms of task dependencies, the activity on the arrow diagram can really only demonstrate F-S, or finish to start dependencies.

Activity on Node Diagram

The activity on node diagrams is also called the precedence diagramming method, or PDM, as well as the node network. Nowadays, it is slightly more common to use this type of project network diagram over the ADM above.

In this project network visual representation, the actual tasks, activities and work are represented as the boxes or nodes. The arrows on the node network represent all the task relationships. Unlike the activity network diagram, the node network diagram uses all four dependencies: F-F, or finish to finish; F-S, or finish to start, S-F, or start to finish; and S-S, or start to start.

Precedence diagrams are also useful for setting and managing lead and lag times. Leads are only used in F-S as a way to allow the next activity, aka the successor task, to advance before the predecessor is finished. Lag times are the delays of a successor activity compared to the predecessor, regardless if it’s any of the four dependency types.

Project schedule network diagram examples

Let’s move on to some network diagram project management examples. These will include both activity network diagrams as well as activity on node diagrams.

Critical path network diagram example

The critical path network diagram is deterministic, meaning the work durations it lays out are meant to be instructions followed by the project team members. Because of this, it is great for scheduling.

This first example network diagram is related to the CPM, or critical path method. Some examples of industries or departments that would most benefit from a critical path network diagram are IT departments and research and development teams.

CPM would use the PDM, otherwise known as the node network diagram, where tasks are in the boxes alongside the amount of time.

Critical chain network diagram example

The next of our project network diagram examples is similar to CPM. The critical chain network diagram is more of a realistic take on time estimates and durations. Because of this, it is more predictive than deterministic.

You see examples of teams using critical chain network diagrams when there are hard limits to resources, as in manufacturing and construction. It comes from the critical chain project management method.

Critical chain project networks are good for using buffers between project completion and the end date. They also help avoid problems like Parkinson’s Law, which is when a task will automatically take the total amount of allotted time; and the Student’s Syndrome, where a task will always be started at its latest possible start date. In other words, there is minimal to zero float in the critical chain diagram thanks to buffers.

Program evaluation and review technique (PERT) network diagram example

Our final network diagram project management example is about PERT. PERT’s main value comes in showing you the shortest possible duration of the project based on the longest path of critical activities. PERT diagrams are probabilistic and predictive.

So what is PERT, the four-letter acronym, when you spell it out? It means program evaluation and review technique. PERT activity network diagram examples are, by and large, seen in one-off projects, or first-time projects where little is known and there are many risks and uncertainties.

A PERT project diagram creates time estimates through a formula that uses as inputs the best possible time, the most likely time and worst-case scenario time. These time estimates, along with the work, are shown on the arrows, with the nodes being milestones, thereby making this an activity on arrow diagram.

How to create your own project network diagram template

In this part we’ll go over the steps to take in setting up your own project management network diagram. The steps are:

Lay out the project work
Create a sequence of tasks
Estimate the duration of the work
Create your project schedule diagram

1. Lay out the project work

The very first phase of creating a network project diagram is to identify all the major project activity. You can use something like a work breakdown structure for this that shows the hierarchy of main work phases, tasks and subtasks of the overall project.

2. Create a sequence of tasks

Step two for project network diagrams is to determine the sequence of activities and tasks. It’s here you consider activities as being related and dependent on one another. You could also separate your critical and non-critical tasks. Gantt charts are also helpful here.

3. Estimate the duration of the work

The third step is to do your time estimates for each task and the overall project. How you do this depends on which diagram tool you use, for example, using PERT’s formula of optimistic, pessimistic and most likely times.

4. Create your project schedule diagram

Now it’s time to visualize the total workflow of your entire project. Pick whether you’ll use activity on node or activity on arrow diagram. Make sure the dependencies are accurate. If you want to add buffers, now is the time.

Our conclusion on project management network diagram use

You know what they say, behind every great project is a great diagram. OK, not everybody says that. But the PMI, or Project Management Institute, says lots of great things about network diagrams on their website and possibly in their PMBOK as well. Or you could ask your friendly PMP (in case you don’t know, the PMP is a project management professional).

Otherwise, to help with network diagramming, you can always check out a project management software comparison chart. You’d be surprised what great PM tools there are for network diagraming, like ADM templates and PDM templates.

We highly recommend you try it out. Maybe you’ll become a network diagram PMP one day too.