What is Critical Path Method (CPM) in Project Management?

The critical path method (CPM) is a prominently utilized project management method for timely project work within budget and time-based limitations. Before diving into CPM’s significance in project management, let us first decode exactly what a critical path method is.

What is Critical Path Method?

Notably, the critical path method is a project management methodology that describes a strategy for successfully identifying activities required to finish a project. It primarily works as a project management approach to help schedule and track different aspects of a project to ensure optimum results.

What is Critical Path in Project Management?

CPM is a widely leveraged methodology by project managers to plan a project pipeline from start to end. This method breaks different stages of a project into separate work tasks, creates a flow chart out of these stages and then aligns the timeline for them based on each task’s significance.

Why Use the Critical Path Method in Project Management?

Though it may look risky to use a critical path in project management, it does have some advantages. And, these are:

1. It improves efficiency and resource allocation. Since project managers identify the most critical tasks, they can prioritise those and allocate resources effectively.
2. It reduces the risk of delays by painting out potential bottlenecks.
3. It helps in creating realistic project schedules, as project managers consider various task dependencies and avoid being overly optimistic about schedules.
4. It promotes better communication and collaboration in the team. Usually, a lot of visual diagrams are used in CPM, which are great for a clear understanding of the project.
5. It encourages informed decision-making, as there is very little room for mistakes.
6. Data gathered through critical path analysis in project management is later used to benchmark future projects.

If you are curious about how project managers handle all this and more, then you can sign up for Edureka’s PMP certification and get live training on such project management methods and more.

But, if you are a complete beginner and hoping to kickstart your journey right from scratch, then check out the project management tutorial to set the base.

How to Find the Critical Path in Project Management?

Now that you have explored so much about CPM in project management, let’s examine how to calculate the critical path.

1. List activities

This is the cornerstone of CPM, where you list and identify each individual job needed to finish your project. The most widely used strategy for this step is the work breakdown structure (WBS). It breaks the project down into smaller, more manageable jobs to ensure that you cover everything in this step, beginning to end.

2. Identify dependencies

Once you have tasks at hand, you need to establish a correlation and find dependencies between them. Dependencies mean a relationship where one task needs to be completed (or at least partially completed) before another can begin. Dependencies can be mandatory or discretionary.

3. Create a network diagram

CPM heavily relies on visual representations of project schedules. These diagrams clearly show the tasks and their dependencies so the team is well aware of their responsibilities. Common network diagram tools include the arrow diagramming method (ADM) and the precedence diagramming method (PDM).

4. Estimate task duration

A project manager needs to assign a realistic time estimate to each task on the list. While making these estimates, he/she considers factors like resource availability, task complexity, and potential risks.

5. Calculate the critical path

This is the heart of CPM. You can use the forward pass method to calculate the critical path.

To do this, you have to start at the project’s beginning and calculate the “earliest start (ES)” and “earliest finish (EF)” times for each task. ES is the earliest possible time a task can start, considering its dependencies. EF is the earliest time a task can be completed based on its ES and duration.

At the end of making the critical path, your calculation should show EF = ES + duration.

Remember that the starting activity always has an ES time of 0.

6. Calculate the float

In CPM, float refers to the leeway or buffer period a task has before it starts impacting the overall project. There are two types of float.

1. Total Float (TF):

This is the total amount of time an activity can be delayed without affecting the project completion date.

There are two ways to calculate this:

• TF = LS – ES (latest start – earliest start)
• TF = LF – EF (latest finish – earliest finish)

2. Free Float (FF):

It is the amount of flexibility an activity has within the context of its immediate dependencies.

You can use this formula to calculate FF.

• FF = ES (next task) – EF (current task)
• Positive float means the activity has some flexibility and can be delayed by that amount without impacting the project schedule.
• Zero float means the activity is on the critical path. Any delay in this activity will directly delay the project’s completion.
• Negative float means the activity has already started later than its latest allowable start time and is currently delaying the project schedule.

The steps may sound very simple theoretically, but the execution part is a bit tricky. You will need to use multiple project management tools to eliminate as many human errors as possible.

How to Use Critical Path in Project Management?

After we understand what is critical path in project management and how it is calculated, we can discuss how to use it.

➢  Compress schedules

You can use CPM to identify ways to shorten your project timeline. It is done with the help of two methods: fast-tracking and crashing.

In fast-tracking, you identify the tasks that can be done simultaneously and get them done.

While crashing, you allocate more resources to a specific task to speed it up.

➢  Resolve resource shortages

CPM also helps in identifying resource constraints. Based on the analysis, you can then move team members, negotiate for budget/time or reschedule tasks.

➢  Compile data for future use

Data gathered through CPM can be used as guidelines for future projects, allowing for more precise calculations. Some of the most crucial data points include task durations, dependency mappings, and the evolution of the critical path throughout the project.

Conclusion

By and large, CPM is a great tool that is not limited to project timeline creation. It supports project managers in their ongoing efforts to sharpen their decision-making abilities and get ready for difficult circumstances.

If you wish to discover more about project management practices, then check out Edureka’s project management courses to redeem that competitive edge needed to thrive in this domain.

Frequently Asked Questions

1.   Is PERT or CPM better?

Both methods are good for different purposes. PERT is good for projects without setting due dates, while CPM is better for projects with strict deadlines.

2.   How is the critical path calculated?

You can calculate the critical path by simply identifying the shortest route on the diagram or by using the formula: earliest finish (EF) = earliest start (ES) + duration. Here, ES will always be 0.

3.   What is the purpose of the critical path?

CPM helps project managers identify the longest stretch of dependent tasks of a project and what can be the shortest time to finish the project.

4.   What is a critical path example?

A very relatable example of a critical path is planning a wedding. The ultimate goal is executing the wedding ceremony, but smaller tasks like picking outfits, booking the venue, inviting guests, etc., need to be completed. So, for example, “choose wedding date” would depend on “book reception venue.”