Don't have the timing of your projects under control? You need to familiarize yourself with the critical path. Read on!
Don’t have the timing of your projects under control? Do they always take longer than you expect? And is it hard to work out exactly why?
You need to familiarize yourself with the critical path. How does finding the critical path make you a better project manager? Read on.
What is the critical path and who invented it?
The critical path of a project is the longest series of activities that affect the end date, because one activity can only start after another has been completed. In other words, make a list of all the tasks that can only start when another is finished. That is the critical path; those are the tasks that have a direct effect on your end date. If one of your ‘critical tasks’ takes a day longer, your project will take a day longer too.
As a concept the critical path only developed in the late 1950s. It was important for the success of projects like the huge American nuclear programme, the Manhattan Project.
Why should you use the critical path?
Every project consists of a number of tasks that have to be done to bring it to a successful conclusion. With large projects, in particular, you can sometimes lose sight of the overall picture and it is more difficult to set priorities. Which task first?
At such moments you may, as a project leader, allow yourself to be influenced by secondary reasons when prioritizing tasks, for example:
- This task is fun and/or easy
- All the documents for this task are ready now
- Person X wants this task finished as quickly as possible
These are not per se bad reasons to start on a task. But if it’s not on your critical path you will slow the project down, and that cannot be the intention.
So the idea is that you should not let yourself be distracted by tasks that are not on the critical path, and that you should finish on time.
Example: building a house
Let’s be more specific, suppose you’re building a house. That has to be done in a particular sequence. Let’s assume a house is ready once the roof is on it. Working backwards:
- The roof can only be added when all the walls are in place;
- The walls can only be built when the foundations have been laid;
- We can only lay the foundations when a hole has been dug;
- We can only dig a hole when the ground has been purchased;
- We can only purchase the ground when we’ve negotiated a good price;
- And so on.
All of these milestones are crucial for the delivery date. Other tasks aren’t. For example: choosing your furniture, laying out the garden, organizing an internet connection.
It is preferable to do these tasks during a particular phase of the project, but they will not affect the end date.
Visualise the critical path in a Gantt chart
You can draw up the critical path conveniently in what’s called a Gantt chart. That’s easy to generate in the Projects module of Teamleader. For each milestone you indicate whether it is dependent on another milestone. If it is, a black line will appear linking the two:
You can see at a glance that you had better not keep the roofer waiting because you want to go to the furniture shop.
The critical path in practice
When you have identified the critical path, prioritize those tasks and make sure there are no ‘holes’.
Marketing expert Seth Godin compares it to a relay: ideally the person in charge of each task passes on the baton to the next, without dropping it. And the person with the baton should encounter as few obstacles as possible.
Godin used to pin green buttons on his colleagues when they were doing a task that was on the critical path. The rest got red buttons; they helped ‘the greens’ as much as possible.
Identify your project’s critical path and give those tasks priority. That way you will be less distracted by tasks that don’t directly affect your end date.