Why loading your professional staff at 66% utilization gets more done

I previously wrote that one way to take care of employees was to load them at around 66% utilization. A number of you asked for research or data to back up that boldish claim.

👉🏼 Queuing Theory

The foundation of my argument comes from Queuing Theory. Queuing Theory is the study of how things move through queues. Think of lines at the grocery store checkout or the counter at McDonald’s.

The data-driven product development expert Donald Reinertsen co-wrote, “Developing Products in Half the Time.” In it, he applies queuing theory to engineering work-in-process. Engineering work is essentially a queue.

The key insight is that when you load engineers at 100%, they cannot 

accommodate uncertainty in the development process. And when uncertainty arises, as it always does, it affects not only the immediate work, but all the work that depends on it.

Everything slows down.

👉🏼 An exponential, not linear relationship

But things don’t just slow down in direct proportion to the variation. The relationship between a variation and the time it takes to complete is exponential.

So under conditions of 100% utilization, something that introduces a 5% change doesn’t take 5% longer, it could take 75% to 100% longer.

Another example is highway traffic and entrance ramps. You know intuitively that the more cars that are on the road, the slower traffic moves. Highway entrance ramps have lights that are timed to space traffic out for this exact reason. There are many factors that affect traffic flow, but the highest volume throughput exists somewhere in the 60-70% loading of the available lanes.

Professional work has similar characteristics of engineering work – work in process, queues and how you load the individuals responsible for the work.

👉🏼 The Pareto Principle

The Pareto Principle makes our final contribution to this discussion. Using it, we can roughly assume that 20% of professional work is responsible for 80% of the value created.

The trouble is management still thinks about loading professionals to fill their capacity. Instead, they should identify the highest priority work to focus on. Then allow space in the schedule for all the challenges that emerge. You’ll have time to address them and continue progress.

How many of you are juggling three, four or more projects? It is no wonder progress is so elusive.