The beginner's guide to Critical Path Method
A critical path is the common method project managers use to map out all the ins and outs of a project. It is a powerful, but simple technique for analyzing, plotting, and scheduling large, complex projects. Once the critical path is identified, you know the least amount of time possible to complete the project, where to compromise, and what to expect.
If you do not know or understand your critical path, you are not making calculated decisions about your project and managing your schedule as well as you could. Having a critical path is one way you can illustrate the most important tasks in a project. In fact, a well-rounded critical path tells you how every task and resource is dependent on each other, so you can see the scope of work you’re dealing with as well as the time frame.
At the same time, there are so many elements that a critical path includes that it can be difficult to lay it all out. We’ve prepared this guide with recommendations, so you could have everything you need in one place.
What is a critical path?
By definition, the critical path is the longest sequence of tasks which must be completed on time to deliver the project successfully. Based on the critical path, you can determine the total time and effort required to complete the project. It also helps you get the overview of tasks and dependencies that cannot be delayed if you want to finish the project on time. So, let’s call the critical path the most important chain of the project. Consequently, tasks that are placed on the critical path can't be moved so there's the need to control them more than others.
There are four factors to consider when understanding the critical path. Estimations, task dependencies, set milestones to be reached, and any critical deadlines defined to keep the project and deliverables on track. The connections between tasks are determined by the requirements of tasks and the project altogether.
In the project timeline, the critical path is often visualized as a sequence of dependent parts. When it is determined by the project manager, a certain hierarchy builds up and the order in which tasks should be completed becomes clear to everyone.
Additionally, the critical path also includes slack, or float time, known as a temporary interval of free time that appears naturally whenever there’s lack of activity. Slack then leads to the emergence of parallel paths, so tasks can be completed simultaneously.
Having the critical path as part of the project management process ensures that projects can run smoothly.
A critical path method example
Consider baking a cake as a simple example of a critical path. You must follow a recipe to make sure you have the right end product. First, you buy the ingredients, prepare the oven, mix the ingredients, fill the pan to bake, and then you let it cool for half an hour. Thereafter you ice and decorate the cake.
It’s an everyday example, but it illustrates the critical path perfectly. To ensure quality and a successful project, you mix the right amounts of sugar, flour, butter, etc. Of course, you can't ice and decorate without having baked the cake. So you can see that in the cake example, the critical path is made up of a number of steps that are essential to making the right cake. If you have a closer look at these tasks individually, you’ll notice that some of them simply cannot be started before the others get finished. That is, one task is dependent on another and determining the critical path requires a clear understanding of the project objectives and the flow of tasks.
Who is a critical path method for?
A critical path method determines the minimum amount of time required to complete a project by identifying those events that can’t be delayed without delaying the whole project.
Because the aim of a critical path is to make sure that no second is wasted, it is more handy and beneficial for projects where task duration is more or less predictable. It can be very well applied to construction projects, event planning, or manufacturing. First time around, it was used to plan and run a major skyscraper project in 1966 to construct the former World Trade Center Twin Towers in New York City.
But other than that, any project that involves complementary and dependent activities can apply the critical path method. Any project that on closer inspection is turn-based, chock full of dependencies, and is more likely to result in bottlenecks will benefit from the structure critical method brings to light.
Why work with a critical path in project management
The critical path is the connection between project scope, requirements, and time. So, managing critical paths in your projects is crucial for a healthy project portfolio and the overall health of your business.
For that reason, there are many benefits of applying the critical path method to your project. Firstly, it gives you a breakdown of all the tasks required to complete the project and the time required to complete them. This makes it easier for you to determine which tasks can be delayed in order to affect the overall completion date. Secondly, it also highlights any constraints that might affect task completion.
In addition to this, the key reasons to use critical path in project management are the following:
- When scoping your project, you understand the sequence of the most critical tasks on your project and, therefore, the shortest time possible to complete the project.
- Following the critical path ensures that tasks are completed in the correct order with attention to the requirements of each task and the final deliverable.
- Determining the critical path for your scoped out project is where the project manager can give the best guidance for the project.
- Visualizing the critical path on a project timeline can ensure that the project can be completed with the resources available.
- Analyzing the critical path helps you take the actions needed to keep a project on track before deadlines are missed. When the project falls behind schedule, you can level resources accordingly to meet the delivery date.
Using CPM further down the line, you can determine if there are any holes in the schedule for your project. A hole is where you or a member of your team can be slacking off when completing tasks. There are many different ways to set up a schedule for your project so one method does not work on all projects, but the critical path method is generally a good place to start.
All that said, critical path is an important concept to master as it is a valuable tool for scheduling projects, be it a home repair or software development effort. Critical Path Method (CPM) is one way of looking at the project schedule. It uses both the logic and task dependencies to determine which activities are critical to completing the project successfully, and which can be delayed if needed. Applying the critical path method to a project is also laying the foundation to help you navigate ambiguous situations later in the project.
How to determine a critical path
If you don’t know how to find the critical path, this section is for you. Determining the critical path is a matter of understanding the tasks at hand and the end goal of the project. One way to start determining the critical path is by defining a project scope. This is done by breaking your project down into smaller packages of work, figuring out their sequence, and setting dependencies.
The CPM technique requires modelling the project in a way that includes the following details:
- A detailed list of all activities required to deliver the project.
- The duration each task will take to complete.
- Dependencies between tasks.
- Milestones that group multiple activities towards a certain deliverable.
You want to work on the critical path and make sure that you’re not wasting any time on tasks that won’t contribute to the final product. When you know the tasks that should be completed first, you can have more time on non-critical tasks which will increase your overall efficiency.
Here are a few steps to follow to make sure you check all the boxes above.
1. Create a work breakdown structure
To have a perfect understanding and visibility of how project requirements translate into action, it’s essential to break down the project into smaller chunks. One way to do it is by creating a work breakdown structure that illustrates milestones and divides them into tasks and subtasks. This is necessary to make the project comprehensive and reduce complicated activities to plain tasks.
2. Define the sequence of tasks
Scoping tasks on a granular level with attention to the flow of tasks is highly beneficial to understand the critical path. In some projects, it’s extremely important to know the order in which tasks can be completed. There are two ways to visualize the order: 1) by setting a start and end date for each task, or 2) by creating dependencies between tasks.
3. Estimate tasks
To figure out the duration of each task, you’ll need to give each task an estimate. This is not the funniest thing to do, but here’s one estimation hack that can help automate this process. Remember that all the way through, you have to keep the communication lines open and make the team part of this process. Project planning is a team sport, and you’ll need their full participation and expertise to know what it takes to complete each task.
4. Set dependencies
Going through dependencies is the best thing you can do in the beginning of the project to avoid being lopsided in the end. Dependencies not only reveal relationships between tasks, but also inform your resource management decisions - you’ll be able to predict at a higher level if there’s a need to hire additional resources to complete the project. With transparency dependencies brought along, you’ll be able to outline the fastest way to deliver the project.
5. Create the activity network diagram
Now it’s time to make sure that your tasks are organized chronologically. This step involves creating the activity network diagram, sometimes referred to as the critical path analysis chart. It’s made to illustrate project deliverables, dependencies, and the sequence of activities in your project. It’s a solution that will help you avoid lengthy texts describing the project to stakeholders and display it visually (including your critical path).
To conceptualize the activity network diagram, project managers usually turn their eyes to flow charts. However, a flow chart can easily become unwieldy and unnecessarily complex, especially if you’re managing multiple projects. There are better alternatives to flowcharts when it comes to visualizing a project chronologically, such as a project timeline, or Gantt chart.
How to visualize a critical path
Having a visual presentation of your project schedule across scoping, resources, tasks, and dependencies guarantees a better flow across all project phases. Because the Gantt chart shares the same components and connections between time, tasks, and order, it is thus one of the best and fastest ways to visualize a critical path and see how the time and tasks line up.
Likewise, visually presenting business KPIs can help everyone stay on the same page, from teams to stakeholders, and increase overall transparency. Yet another benefit, scheduling tasks on an interactive Gantt Chart will help you improve the understanding of the progress on key project milestones.
But there’s one more thing. Let's say you’ve already scoped out the project. What's next? Tasks are defined and planned out, the team knows what to work on, when, and the project's milestones are visually presented with indicators showing the current status. However, we still need to find the resources to execute the tasks. This is where adding capacity management to the picture is crucial.
While you might have an understanding of who will be assigned to the project, it’s still important to check if your project schedule doesn’t contradict the person’s workload and schedule on other projects. Heatmaps that showcase the entire resource pool turn out to be great for figuring out what’s everyone’s availability for the next months:
Capacity management ensures that you have the resources needed to perform the tasks you’ve set up to complete. Connecting scoping and resources is primarily based on factors such as the time estimations of tasks and the total available working hours of each role on your team. So if resources are connected in the scoping process, there is extra attention to the capacity limits in the schedule.
Critical path analysis
Critical Path Analysis is an important part of your project management plan where each activity is given a timetable for its execution and delivery. These activities have dependencies, risks, and resources associated with them which are outlined in the activity list. Once all of these factors are considered, you can then determine the "critical path" of activities – that is, the total duration required to deliver the project. Critical Path Analysis can help project managers reduce bottlenecks and delays caused by dependent activities and even re-allocate resources to improve the completion date or outcome.
In short, analyzing the critical path can help you understand the project, potential delays, and the expected delivery. A project can have several critical path sequences, and have a direct impact on whether deadlines are able to be met. Any delays happening in the critical path can have significant consequences for the further progress.
Using data and visual insights can greatly improve your chances of avoiding delays in projects and along the critical path. Combining project and resource data from your company with a visual schedule and live insights can give you the perspective you need to make the right business decisions. To ensure profitability and swift decisions the critical path must show when the project needs to be completed.
Insights such as a burn up chart, sprint burndown, or the cumulative flow can give you this overview of your projects’ progress. These insights help project managers detect the health of a project and give stakeholders the information they need to make the best decisions for the future of the company.
Conclusion
Although not a widely used technique, the critical path method (CPM) remains an important tool for project managers to successfully deliver projects on time and within budget. It is a one important tool that will help you control the risk involved in any activity.
Defining the critical path begins with understanding the scope, the requirements, and the natural development of the project. Combining project and resource data to form a better perspective gives you the overview to make the right decisions for your projects.
Visualization is known to be one of the key elements in understanding and gaining insight. Using visual components such as Gantt charts, burn-up charts, total utilization levels, and a schedule that connects projects, people, and scoping, gives you a better foundation for making the right business decisions.
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