Project management is akin to a complex puzzle; each piece (or task) must be placed and oriented correctly to reveal the full picture at the project's completion. However, there's always that critical path: the string that weaves through every puzzle piece, ensuring they're interconnected and completed in the right sequence to avoid project derailments.
In this article, we’re going to look at the critical path method (CPM) and what it entails for project management, with examples of software that can use it. We’re also going to cover all the practical applications relating to it, such as how to calculate a critical path and how to calculate important items such as late start and late finish.
The critical path method (sometimes referred to as critical path analysis) is a tool used by project managers to estimate timelines for their projects. Essentially, a critical path is the longest sequence of events, from start to finish, that need to be completed to finish the project. These events, normally referred to as critical tasks, are the tasks that are crucial for a project’s completion. A delay in any one of these tasks delays the entire project.
Thus, we can reasonably infer that the critical path represents the minimum time required to finish the project without compromising quality. This makes it a very good tool for estimations and reducing delays for a project.
Important Terms And Abbreviations
How To Implement Critical Path Analysis In Project Management?
To calculate and implement a Critical Path Analysis, project managers must break down the project into tasks, identify dependencies and use the data from this to create a network diagram either manually or by automation (software).
Let us consider the launch of a new product as an example of a project that uses the critical path method. The product is broken down into phases such as market research, product development, design, testing, marketing, and launch. Tasks like testing are critical tasks, as any delay in these types of tasks would lead to a delay for the entire project.
Thus, to effectively manage this project, managers focus on prioritizing critical tasks, allocating resources efficiently, and implementing robust risk management strategies for the projects. This approach helps to minimize delays, optimize workflow, and increase the chances of a successful launch.
Projects get delayed due to a variety of reasons, whether it’s human error or unforeseen consequences or even an Act of God. However, the most common reasons are related to poor planning, resource constraints, and scope creep.
CPM can help tackle these common causes as its focus is on prioritizing critical tasks, which ensures the project's scope remains grounded. Additionally, it also helps with efficient scheduling, leading to a proper allocation of resources and less chances of reaching a bottleneck. Finally, it helps in monitoring and tracking progress, meaning that managers can now make timely corrections if the project isn’t going as per schedule.
The following steps are necessary to manually calculate a critical path:
Identify All Tasks
The very first step involves task identification so that the project can be broken up into parts. Every task that’s required to finish the project must be listed. You can utilize a work breakdown structure (WBS) to break down the project into smaller, more manageable tasks.
Determine Task Dependencies
Task dependencies refer to tasks that can only be started when a preceding task has been completed. Thus, tasks that depend on others must be determined to ensure that the tasks are properly sequenced. Additionally, managers may make use of diagrams such as PERT and Gantt Charts to visualize the relationships between tasks, making it easier to follow.
Estimate Duration
Assign realistic timeframes for each task based on previous experience, expert opinions, or industry benchmarks. However, that’s not all: managers must be wary and account for any potential delays or unexpected challenges that may crop up and delay tasks.
Create A Network Diagram
A network diagram is a visual representation of the project where the tasks are visualized as nodes and dependencies as arrows. This diagram helps in giving an overview of the project and can be passed between managers to give a quick snapshot of project completion.
Calculate Early And Late Start/Finish Times
Once the diagram is completed, the next step is to assign early start/finish times to tasks along with late start/finish times. To calculate these times, project managers can use either forward pass or backwards pass.
Forward and backwards passes are calculation methods used in the critical path analysis to figure out the earliest and latest start/finish times for each activity. A forward pass method involves moving from the beginning of the project to the end, calculating earliest times for each task based on the previous ones. As a result, it gives you the earliest start and finish dates.
Conversely, a backwards pass moves backwards—it moves from the end of the project to the start, calculating the latest finish times for each task based on the task coming after it. Hence, it gives you the latest start and finish dates.
Identify The Critical Path
Now that all the timestamps and duration for all tasks have been calculated, the only remaining thing left is to add them up to calculate the time to complete each path. The path that has the longest time will be the critical path.
So far, we’ve covered the manual approach to determine critical path. The manual approach has its advantages: it offers a deeper understanding of the project; it does not need any prerequisite like project management tools. However, it can also be time-consuming, riddled with human errors and impractical for large scale projects.
This is where automated calculation comes in. Today, many project management software automates the critical path process based on user input. These inputs include details such as dependencies, durations and other task details. Once these details are entered, the software automatically creates the network diagrams, performs forward and backward passes, and visually represents the critical path.
Automated calculation certainly has its pros: it’s very efficient and can handle large scale projects that are too complicated to work on manually; it provides real time updates; it lessens human error. However, it also has its drawbacks: it’s heavily dependent on the accuracy of the data, meaning that if the data is inaccurate, then the resulting critical path will also be inaccurate. It’s also too much for small-scale projects where the manual route is the more cost-effective route.
