What is the Role of the Critical Path Method in Project Management?
A healthy project lifecycle is what leads businesses to victories and effective results. Every manager should know what to do at every stage, including the critical path method identification.
This method involves mapping out critical tasks necessary to complete projects.
The value of defining a critical path in a Gantt chart is not in doubt, and the method itself serves as a reliable helper for many project managers worldwide.
In this post, we describe the role and power of CPM, sharing a real-life example, tools, and everything you need to know to apply it correctly.
Let’s start with a theoretical block.
What is the critical path method?
The critical path method (CPM) is a technique for scheduling project tasks and other activities. It looks beneficial for managing large and complex projects. CPM determines critical and noncritical tasks and prevents timeframe problems.
The method means that each task is arranged in sequential order, along with a time estimate. An activity occurs when your task either begins or is completed. This info is then reflected on a CPM chart.
Example: suppose you are cooking a meal.
You want your veggies and chicken to be ready at about the same time. However, it doesn’t matter if you lay the table an hour early or whether you lay it ten minutes before you’re ready to serve dinner. The timing of your vegetable and chicken preparation is essential; laying the table is less critical.
The roots of CPM
What is the history of the method?
CPM was developed more than 60 years ago in the US. Its authors — James E. Kelley and Morgan R. Walker — used it for agricultural projects and construction work. They wanted to find ways to reduce the costs associated with plant shutdowns and restarts caused by inefficient scheduling.
They quickly realized that excess costs could be avoided, instead of saturating the problem with additional labor.
The interest in the critical path method had diminished by the early 1960s. However, some companies began to utilize it to oversee complex projects (for example, Catalytic Construction and Mauchly Associates).
Today the method is conveniently adapted to various fields, including software development.
The process of applying CPM continues to get easier. When the method was created, managers had to find critical paths by hand.
Nowadays, you can save valuable time and avoid composing tables using the online critical path software solutions.
What are the benefits of CPM?
Here is the list of the expected benefits associated with the critical path method:
1. Improved scheduling
The segregation of critical and noncritical tasks allows for more efficient task scheduling. This process permitted through the critical path determines those essential tasks to the successful running of your project.
When you understand where the alterations can be made, you get your critical processes not impeded, and your project remains on schedule.
2. Enhanced project management
We can’t evaluate the advantages of using the critical path method without mentioning the benefits for PM.
With the help of the CPM, you can break apart substantial undertakings into elemental parts. This division creates individual and discrete tasks that significantly enhance and simplify project management.
The critical path also ensures the proper allocation of resources (including human resources).
3. Better human resources distribution
You can choose one of the ways to distribute human resources enhanced through the critical path.
The method helps new team members to be placed on noncritical project elements. It is rather important as they can learn more about the project, accomplish milestones, and not cause an interruption on the project flow.
4. Budget control
If the budget is tied to subtasks (rather than the project as a whole), spending issues are recognized pretty easily. Therefore, you can solve them more effectively and in a manner that can save overall budgetary parameters.
Now it’s time to recall some disadvantages of CPM
What are the CPM drawbacks?
The method is known not only because of its benefits. It is also associated with some disadvantages.
Here are some of them:
- Creating a CPM diagram can take a lot of time and effort.
- It doesn’t adapt well to making changes on the fly.
- Your schedule may look hopelessly optimistic if you do not control the resources you need to complete the critical path on deadline.
What about the example?
Now it’s high time to see how CPM works in practice.
The example of the critical path method
CPM works incredibly well for projects with short deadlines.
Suppose your goal is to plant a tree in a backyard.
You have to set all the steps to show how to do it. To complete this simple project, you’ll need to list all the tasks required:
- Choose a place in the backyard.
- Buy a shovel.
- Choose the right seeds.
- Dig a hole.
- Fill the hole with water.
- Plant a tree.
Note that some steps cannot start before the others are finished because they are dependent.
The activities “Dig a hole,” “Fill the hole with water,” and “Plant a tree” must be done in a specific order, so they are sequential steps.
These activities and the first one (“Choose a place in the backyard”) are the essential critical actions to get the solution. You should place them on a critical path for our project.
As you see, you cannot start some activities until the others are finished.
Now you can easily calculate the length of your project. Define the approximate start time for every step on your critical path.
- Choose a place in the backyard — 30 minutes.
- Buy a shovel — 30 minutes.
- Choose the seeds — 30 minutes.
- Dig a hole — 10 minutes.
- Fill the hole with water — 5 minutes.
- Plant the tree — 15 minutes.
When you summarize the durations of all your critical tasks, you’ll get the time to complete your project. In the mentioned example, it is 2 hours.
Now, let’s consider how the critical path method is used in practice.
How to plan CPM: six consistent steps
1. Specify your tasks and activities
Prepare all your tasks and make a list of only higher-level activities. It will help you to divide your activities into manageable sections.
Use tables, lists, or tree structures for this aim.
2. Set dependencies
Remember that some tasks will start when others are complete. Listing the predecessors of every action will help you identify the appropriate order.
3. Visualize a critical path
Having the identified tasks and their dependencies, you can compose a critical path network chart.
This chart will help you to view projects broken down into separate tasks. Arrows, boxes, and circles will demonstrate these tasks and dependencies. Then you can name every activity and highlight the paths.
Luckily, there are many reliable online project management tools to draw such a chart, so you will not need to do it manually.
4. Estimate the time of tasks completion
You can estimate the time required to complete all your tasks even if you do not have enough experience.
Use days or weeks for measuring (it depends on how small or complex your projects are).
5. Identify critical paths
Now you’ll have to highlight the core parameters of your tasks.
- ES is The earliest start time. It is when an activity can start once the previous dependent activities are completed.
- EF is the earliest finish time. This is ES + the period required to complete the activity.
- LF is the latest finish time. It is when an activity may be completed without any delays.
- LS is the latest start time. This is the period required to complete the activity.
Pay attention to the float time between ES and LS or between EF and LF. The tasks can be delayed without delaying the finish date of the project during this period.
The chart will assist you in identifying the longest path of any task and the most extended sequences.
6. Update the chart
This chart should be updated to let you recalculate your critical path. This will lead to a more realistic view of your project.
Calculating the critical path method: everything you need to know
To calculate a critical path, you will need a reliable online tool.
Some people still do it with Excel. It may serve as your CPM software if you plan a small project and need to identify critical paths.
However, professionals rely on more powerful and multifunctional software solutions, such as GanttPRO. It helps to understand that identifying a critical path in your project is a pleasure.
How to calculate a Gantt chart critical path with GanttPRO
GanttPRO does all the hard work for you. Enabling a critical path in this Gantt chart maker requires just a couple of clicks.
- Start with creating your project and setting all tasks/subtasks.
- Set start and end dates, durations and identify all predecessors.
- Add task dependencies and project milestones. Use the drag & drop feature to do it quickly.
- Now you can adjust the view of your project to identify the critical path. Open Settings and click to switch on the critical path. This chain of important tasks will be shown in red.
Conclusion
A critical path method CPM is aimed to undertake your project efficiently, without delays and interruptions.
Applying the critical path method will help you understand that this approach is helpful for any planning phase. It’ll give you the correct completion date of projects and the flexibility to float activities.
With the CPM in project management, you will be able to focus your efforts on professionally optimizing work.
Keep reading the full article here: How Critical Path Method Drives Project Management Success https://blog.ganttpro.com/en/critical-path-method-cpm-in-project-management/.
