Without proper scheduling, no construction project would be completed on time. The foundation of that project schedule should typically be made up of the tasks that are essential to keep the project moving. That brings us to the Critical Path Method which is widely used in the construction industry. Utilizing the Critical Path Method might be a little intimidating at first blush, but it’s simple at its core – plus utilizing it’s a great way to make projects more efficient.
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What is the Critical Path Method? What’s a “Critical Path”?
A critical path is the longest sequence of activities on a construction project. This will determine the maximum amount of time needed to complete the project. The Critical Path Method of project scheduling (CPM) focuses on the key (critical) tasks that must be performed, and what order they need to be performed in. These tasks are identified, and making sure they’re performed (and performed on time) ensures that the project remains on schedule.
What Makes a Task “Critical”?
The critical tasks identified are tasks that have “zero float.” You can think of “float” as “slack” – it’s the term used to describe any leeway or budgeted time to spare between tasks. So, “zero float” refers to a situation where there’s no time to spare, which is typically the case with critical tasks. Critical tasks are the ones that, if not performed and performed on time, the entire project will suffer delay.
Speaking of Delays…
How to Create the Project’s Critical Path
There are numerous different software programs available that will calculate your project’s critical path. It’s one thing to have a critical path set up on your project. It is another thing to be able to understand how to implement it.
The first step is to list off all the tasks that need to be completed on the project. Start with the earliest task, determine what needs to be finished next, and so on. You can then begin building your diagram. List the first task, then what tasks can be completed after that one is complete. You’ll end up with a linear chart that shoots off but eventually merges at the end.
Next up is assigning the estimated time of completion for each task. This is accomplished by taking the average of best-case, worst-case and most likely scenarios. At this point, you should have a chart with all the tasks listed, what tasks are dependent on the other, and the estimated time of completion.
Now its time to identify the critical path.
Without going into too much detail, this is done by taking assigning “early” start dates and finish dates, then “late” start dates and finish dates for each task. You now have an overall view of how long the project should take. Any tasks that don’t allow for slack are critical tasks. Meaning, they must start and finish at certain times to keep the project on schedule.
Finally, you’ll a complete critical path schedule for your project. This chart will not only identify the critical path but also the non-critical tasks, plus it will show much float time is allowable to keep the project on schedule.
Advantages of Using the Critical Path Method
The Critical Path Method increases visibility by allowing everyone on the project to understand how the individual tasks fit together and how they affect the overall project’s duration. By dividing a large project into a series of smaller tasks, management and oversight are easier, and delays (critical or non-critical) are readily identifiable. However, the critical tasks will need to be supervised with more attention than others to fully realize the increased efficiency and cost controls that the Critical Path Method provides. Establishing a critical path schedule is just the beginning. The CPM schedule will need to be updated and monitored regularly to ensure its effectiveness.