Years ago, when most of us in the project management software industry were discussing critical path theory and how resource levelling should work, a new paradigm emerged called Critical Chain. It was developed by Eliyahu Goldratt. The issues that caused Critical Chain theory to evolve were sound. The problem with Resource Levelling is that it assumed a perfect world with perfect distribution of resources and a world where when one task was complete, the next task and its resources would immediately be available. Of course that’s not always the case.
If we focus on where the resources become critical, the theory went, we could focus on actual work rather than theoretical work. After all, actual work is accomplished by applying resources to outstanding work.
The paradigm was picked up by some project management tools but not many and the popularity of the algorithm was obscured by new developments in communications and collaboration but there are still some aficionados of the methodology who swear by it.
If you’re thinking that you’ve never heard of or care about Critical Chain Methodology, think again.
Been to the airport lately? If your project schedule is a commercial aircraft then you’ve been living critical chain for sure. The critical resource is, sadly, not you. It’s the aircraft. The next most critical resource is, again sadly not you, but rather the crew. Critical chain methodology would say, let the non-critical resources queue up and stand by for the much more critical resource to appear.
So, you get a notice to appear at the airport 2 hours prior to your flight. In some airports, that’s 3-4 hours.
Is the plane there? No.
The crew? No.
But you’re there and you’re definitely important to the project schedule at some point in the process. But not now. In the meantime, queue up and wait.
That’s because the project isn’t you. The project is getting the plane through it’s schedule as efficiently as possible. You’re not the project. You’re the cargo; what’s delivered in the project. If you arrive or not, that’s much, much less important than the arrival of the plane on time at its next destination.
One hour prior to your flight, if all is going well, the all-important aircraft appears. One crew possibly deplanes. Another boards. Critical resources like fuel arrive and are loaded. Critical resources like Maintenance check the tires and make sure all is ready to go.
With 30 minutes left before departure, the least important resources to the project are loaded. Yes, that’s you. The passengers are loaded in what airlines hope is the fastest path to getting onto the plane. Some airlines load from the back to the front. Others load from the outside in, putting window passengers on before aisle passengers. If some of these least critical resources don’t appear. The project isn’t delayed. The plane still leaves as close to schedule as possible. It has other critical project resources it has to account for such as air traffic control space and other airport gates when it lands.
As someone who travels by plane often, I often wish that the plane project was oriented around me but that’s just not so. I’m the most available resource in the entire equation. There are hundreds of me. There is only one plane.
So you may not have used critical chain in your own project schedules thus far, but it’s certain that you are encountering the methodology every day in your day-to-day activities.