The Critical Path is a series of tasks that extend a project to its longest finish date. Tasks that depend upon previous tasks, causing a project to finish at the latest time.
A project’s critical path is your longest route from start to finish. In other words, your project cannot be finished any quicker than through this series of tasks. Eliminate or shorten some tasks, and your project will be completed sooner.
Critical Path Analysis (CPA) is a management tool that:
- Sets out all the individual activities that make up a larger project.
- Shows the order in which activities have to be undertaken.
- Shows which activities can only taken place once other activities have been completed.
- Shows which activities can be undertaken simultaneously, thereby reducing the overall time taken to complete the whole project.
- Shows when certain resources will be needed – for example, a crane to be hired for a building site.
In order to construct a CPA, it is necessary to estimate the time and resources for each activity – that is the time taken from commencement to completion.
Then the CPA is drawn up a based on dependencies such as:
- The availability of labour and other resources
- Lead times for delivery of materials and other services
- Seasonal factors – such as dry weather required in a building project
Most projects contain a large number of tasks. The critical path is the order of tasks that must be finished for the project to be considered complete. This path dictates the final finish date of your project plan.
The critical path is not primarily a list of vital tasks. It is a specific sequence of tasks, each task depending on the last.
As the project progresses, different sequences might be named as critical. Consider a project with two vital task sequences which we'll call selecting the new office site and Moving in to new offices. At the onset, the first task is projected to take 9 months and the second is projected to take 6 months. Since the first task will take longer and is deemed as being on the critical path.
After three months work, should the first task perform ahead of schedule with a new estimate of 5 additional months more while the second has been delayed by three moths the latter task would now be on the critical path?
What is a Critical Task
The definition of a critical task is any task that with a change of duration may positively or negatively affect the end date of the project if delayed
Tracking the Critical Path
The Gantt chart and network diagram two classic views in MS Project will display critical tasks and links in red automatically to make these tasks easier to observe and report.
Total slack is the amount of time that lies off the critical path. In other words changes to the duration of these tasks may or may not affect the critical path.
Slack is the amount of time a task can be delayed and still be on schedule. A 5 day task with a 10 day deadline has 5 days of slack. A task with no slack is automatically critical. Imagine two tasks due to finish at the same time. Packing computer equipment with one day of duration and packing files with four days duration. If they both started at the same time the pack equipment tasks would have three days of slack
What can a business do if a project is delayed?
- Firstly, the CPA is helpful because it shows the likely impact on the whole business if something happens to a segment.
- Secondly, if there are resources elsewhere, it might be possible to switch these to help catch up on the delayed activity.
- As a rule, most projects can be brought back on track by using extra labour – either by hiring additional people or overtime. Note, there will be usually be an extra cost. Alternative suppliers can usually be found – but again, it might cost more to get urgent help.
Why define your business critical path
- It shows that your business requires careful planning to run smoothly
- Improves efficiency and cash flow, so resources can be utilized needed
- If problems happen they can be identified quickly, this will mean that informed decisions could be made
- Sometimes you can offload tasks to other resources, effectively shortening it
Consider a simple project with 1,000 hours of work, all performed by a single person. The critical path is that single-path sequence of tasks. Task 1, then 2, then 3, and so on… You get the idea.
What if you added another person who could do the same work? The project would then be completed in 500 hours, utilizing two paths. But do you have a second person?
This is the crux of project management - juggling time, resources, and cost to maximize productivity.
The shortest route through a series of interrelated tasks. Should a task on the critical path slip then the end date of the project would be jeopardized.