Critical chain vs critical path in project management

By Kishana Citadelle
Published: 8/25/21
definition backgroundCritical chain vs critical path in project management

Projects executions have been the same for ages. Yet, project managers and project teams, seem to encounter mishaps in their schedule and, probably ones that could have been avoided, if the right help was available. So, as you may understand, the proper end to a project is very important as it not only helps the company gain value but also pleases the customer who could be loyal in the end. So, what’s the harm in using the correct tools for your project? Therefore, that is where critical chain method and critical path method come in?

What is critical path?

Critical path management (CPM) is a method, used in project management, that models projects. Critical path is where you put every important components of your project and produce the ideal timeline (schedule) for achieving it. In your model project, those elements can include: tasks, the tasks advancements, roles, risks or finished products.

The purpose of critical path method is for the project team to get one task done before the other. So that when the project manager reviews the path (from one finish task to the other), he can codify the main resources and tasks of the path according to their importance for the next one and schedule.

But of course, there are always little incidents in project management, that create late project finalization. Usually a project manager and project team would want to avoid such critical path situations in project management needing to finish the project on time to avoid any further cost.

Which is why in project management, the project manager would focus on the longest task of the critical path, to regulate the problem. Think of the critical path’s method as a real life situation; you have a few tasks to do by a certain time, you would typically sort out and plan according to the longest one to finish quicker. Well, that is what critical path looks to achieve.

How does it work?

  • Divide your project into tasks: It is important to know the tasks you must complete to create a schedule or, there would be no critical path for the project nor duration estimation. Don’t forget to assign the tasks of the project to the workers by name.
  • Identify your task by order of importance: Well, it is necessary to do the pressing tasks first in a project so as not to be late and have many project delays and prolong the duration. It’s a total step-by-step method.
  • You can choose to create a diagram: Critical path is the total visual representation of the project’s tasks, simple and clear for everyone to see.
  • Duration estimate: Take notes of the duration it will approximately take to complete the project.
  • Check your resources: Are there enough for the project’s total completion? If not, then it creates issues such as delays for the project, project management and increase in budget cost for the company and long project duration.
  • Finally, you can determine your critical path by locating the longest task in the project to start with and get rid of so as not have it hinder the other tasks, which could lead to project schedules step backs.

Critical path methodology uses the resources to schedule the activities in the project to accomplish and because you must finish one task before the other, they are done in a sequenced​​ method.

What is critical chain?

Critical chain is a method used in project management as well, developed from the critical path method. Its method’s goals is the same as critical path method, in terms of looking to finish a project on time, hopefully within the estimate duration. Its method focuses more and centers around the resources such as the team and equipment, etc. needed to finish the job for the project.

The critical chain method (CPM) is also the longest set of tasks in the schedule that considers the limited resources that may have or could delay the project. Once you have found the problem, critical chain, seeks out what the schedule contains and faces the problem by trying to solve it in the quickest way to reduce delays and being late in order to finish the total project.

Furthermore, it is just like critical path method (CPM) because you must finish a task before starting the other. No multitasking is accepted. And because, its objective is to prioritize organization and efficiency of the project by having enough resources, every task should properly be finished before entering a next phase. And you are probably wondering why? That is because, it has been shown, or you may have even experienced it.

For example, when you look to start working on many tasks at the same time and because they were too many to handle becomes critical. What could have been done decently, is now rushed and a total lack of quality.

So, the same goes for a company looking to do a job and creating a product for a customer. With it being so rushed, that when it is finished, the total quality is lackluster. Now, how is critical chain used to avoid this?

How does it work?

Before you implement any tool in a company or for any project, it is important to know your job first, then look to understand how critical chain works. And critical chain can be done by steps, which are:

  • Start to determine all your activities and resources which make up your critical path. Including this step is essential, so you know which tasks are important.
  • Create a schedule/ estimate duration to know when those have to be done by. Every project professional paid by a customer has a deadline. This step should not be overlooked. A scheduling software can also be used to aid in the planning of project management.
  • Include resources constraints for your critical chain: it is always good to expect the unexpected in your planning and schedules of project management. This could be helpful to detect any problems on the job you might have when employees are assigned to their tasks. Do they have sufficient materials to last to the end of the job or project?
  • Determine the buffers: you can never be too sure of your set schedule and deadline, so you add extra time to tasks to avoid more delays, if there were to be, to the project. Of course, the more the risk, the more buffers should be added to a project chain for security. Therefore, they are classified by types. You have:

    The project buffers: it is placed in between the last task and the project’s final date, particularly after the last task and before the end date. It is basically used as the plan B for the critical chain. That’s where the delays can be found.

    Feeding buffers: It concerns the non-critical chains. They make sure that they don’t affect critical chains.

    Resource buffers: they concern the sufficient resources or not for the critical chain.

    • Oversee the project: the project and buffers should continuously be checked as long as the project is not completed. It helps the project stay on track, determine or prevent any issues that might appear.

What is the difference between critical chain and critical path?

  • The critical path (CPM) focuses on managing tasks, whereas the critical chain concentrates on managing the resources and buffer.
  • The critical path method (CPM) is more of an estimation than the critical chain, as it assumes that every resource will be available when needed. On the contrary, the critical chain takes that limited resource and uses the readily resources to plan out a realistic schedule.
  • In critical chain method (CPM), the buffer (added extra time) is for the whole project, whereas in critical path is for the individual activities.
  • No multitasking is allowed in the critical path (CPM) as a project task can’t be completed before the other so, the next activity can’t begin before its start time. And something to note, is that even though, you may finish the task earlier than its due time, project members have to wait for it to be completed before you start the other. On the other hand, the critical chain prefers when an activity ends earlier, to start on another one, with the added time inserted in the buffer (added time of the project).
  • Therefore, there are delays of schedule in critical chain on non-critical activities whereas in critical path the project members can immediately start on non-critical activities.
  • In the critical path, work increases if an activity has extra time, which isn’t the case in a critical chain with the real-time length and buffer for every activity
  • In critical path, the float or slack (added extra time) to each activity of the project were misused and lead to delays in projects.

Benefits

Benefits of critical path method

The benefits of critical path method (CPM) are that it is used to provide efficiency for complex management and differentiate the tasks from the most important to the less important in order to effectively complete a task. All the tasks are visible and identifiable.

  • The critical path method’s (CPM) use is to increase effective scheduling in projects
  • To organize complex projects’ job and project management
  • Its use is to help identify the main tasks of the project
  • Its use is to save time and reduces cost for the project and project management
  • Enhances project management
  • Helps control budget cost: with the association of cost and resource, the critical path method tells you what is making the project to stall and go over budget.
  • Project management can use it to determine critical activities that need attention in the project
  • And you can also get and use a graphical representation of your project

Benefits of the critical chain method

  • It eases the total planning and total control process of the job
  • Planned estimate total time (duration) and total cost for the project
  • It reduces the time and cost of project management
  • No multitasking allowed, preventing disorganization, switching from tasks to tasks, which could create confusion and prolong the project process. Basically, creating delays
  • The total amount of tasks is limited, and tasks are added to a project only if the resources are sufficient.
  • The resources can be easily assigned to the project workers
  • Buffers are added at the end of the project, to predict unfortunate, critical events, limited resources in the project and prevent delays of the job
  • The project workers can focus on one task at a time, avoiding confusion and delays
  • Finally, critical chain’s total use is to achieve a successful project with sufficient resources, withing the planned duration, budget, schedule of the project. Its use is to prevent project slacking on the job, issues within the worker's circle and have successful work days for a fast finalization of the project.

Can critical chain be shorter than critical path?

Project managers would use the critical path method’s (CPM) as the duration of the entire project by raising its duration to add extra time to the schedule if needed in case of any delay on a task or job to predict further delays which could really affect the project’s finalization.

But of course those extra time added, had the wrong impact on the schedule. That is where the upgraded, the latest version of the critical path intervened. The critical chain was created.

Critical chain is the upgraded version focused on the resources (workers, equipment etc.) needed to complete the project. These resources focus would apparently decrease the duration of the project completion.

In critical path (CPM), you don’t gain by adding extra time because you only add the delay. Finishing an activity early or earlier does nothing, as you can’t start the next activity before its start time.

Float can also be misused in critical path (CPM) and lead to the student syndrome. Because, as workers feel that the activity has added time, believe they can start later than the start time. Using the added time of the activity as a sign of, I can start later.

So, even though critical path method (CPM) may seem longer in terms of added delays and non-advancements and critical chain focuses on a realistic schedule by really thinking of the uncertainties of the job in a project. It is the preparations and adding buffers at the end of every activity for critical chain that draws out the project management. You have to make sure the buffers are correctly added. It is the process that can take longer than that of the critical path.

To conclude, it seems like there is no true winner here between critical chain and critical path of a project. Furthermore, it depends on the size and complexity of the project and the company’s organization. But that does not mean that critical path and critical chain is not a help when it comes to estimate duration of an activity or project, budget cost and resources available, which are the main things for a successful project.

If you start by sorting it out all the essentials for the project, it starts with a good beginning, leading to a fruitful project.

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