Is the Critical Path Method Still Valid?

Not in my environment, here’s why––it’s does not mention the work resources in the definition. You see, the competition in our industry is very competitive. Our competitors offer new features and better ways of doing things. Some of it is marketing hype, but our customers don’t seem to notice. Price is always an issue. Our customers have folks dedicated to getting the best price from their supply base. Of course, the quality of our product has to meet or exceed specifications. Our industry is regulated and major penalties have been imposed on those companies who have faltered. What does all this have to do with critical path? Who does all this work in our company? Our most important resource––people!
 
And, like everyone else, customers want what they want now. Even when the items ordered from us are being developed and manufactured for the very first time. The lead times we offer are always too long. OK, they say, then tell me when I will get it. We look in our crystal ball and tell them six to eight weeks. And, six to eight weeks later we still haven’t shipped their order. What does all this have to do with critical path? What information are our people using to set these order lead times? The estimates our project managers tell them based on their critical path plans.

The Critical Path

Here’s what I’ve learned––the critical path is defined at the longest path of task dependencies. In a project, we need to do one task and deliver the work of that task to the next task. This next task is dependent on the work of the prior task. Yes, there are many paths through the project, but when we know the longest path we have some idea about how long the project will take to finish. We also know when it needs to start. That’s the theory, at least.
 
But, my team tells me that they already know all this and that’s how they estimate the lead time we tell our customers. I look at them with a slight kink in my neck since our ability to meet the estimates they provide is so poor.
 
I asked some of my project managers if their critical path takes into account the resources who do that work.
 
They tell me, of course, they assign resource to every task in the project plan. Fine, but that’s not what I’m driving at.
 
I ask, does it every happen that we want to start a task, but the resource we’ve assigned to do it is not available.
 
Oh, they say––all the time! So, I ask, if the resource is not available when you need them doesn’t that extend the length of the project?
 
Of course, they say, that’s why we are always looking to add more people to our team. This is a very common issue.
 
I see they are not with me. I ask again in a different way. If the longest path of tasks determines the length of the project and if the unavailability of resources can also extend the length of the project, what’s the result? We can’t be providing reasonable estimates.
 
So, we are dependent on the resources, and the task dependencies, to determine the length of the project.
 
And, that’s usually where the conversation ends or moves to another topic. They have no answer for it. Neither do I, if I’m honest.

A Small Light At the End of the Tunnel

The length of the project must include resource dependencies and task dependencies. The critical path method does not do that. So, why are we using it? I’m talking to the wall.
 
Without taking resources into account it make it difficult to plan the current and future load on our resource. No wonder we never know in enough time which resources are in short supply. When resources are in short supply, it puts more stress on everyone else. And, the stress in our environment is high enough already.

A Better Approach

We need to find a solution which does include task and resource dependencies. We need to get a better handle on how long a project will take. Not only to give our customers better information, but also know the load on our resources.
 
A quick Google search on “includes task and resource dependencies” results in finding this: “For the critical chain method, you would take resource constraints / dependencies into account when planning projects.”
 
What is this critical chain method anyway? This seems promising and seems to fill that gap in planning task and resource dependencies. I’m going to go find out more about it, but first I have to deal with the line of folks waiting to see me.