“We need everyone fully utilised.”
It sounds like good business. After all, if you’re paying people to work, shouldn’t they be busy all the time?
Many organisations believe that maximising utilisation maximises productivity. They allocate teams at 100%, or even 110%, capacity and expect more work to be delivered.
Yet the opposite often happens.
Deadlines slip. Priorities compete. Quality declines. Teams become overwhelmed. The business grows frustrated because, despite everyone being “busy”, value reaches customers more slowly.
The problem isn’t your people.
It’s your understanding of capacity.
The myth of 100% utilisation
Imagine driving on a motorway.
At 20% capacity, traffic flows smoothly.
At 50%, vehicles move efficiently.
At 80%, traffic is still flowing well, although drivers begin adjusting their speed.
But what happens at 100%?
One car brakes unexpectedly. Another changes lanes. Suddenly traffic grinds to a halt.
The motorway didn’t fail because there were poor drivers. It failed because there was no room left for variation.
Organisations work exactly the same way.
People don’t work in perfect, predictable environments. They respond to customer requests, solve unexpected problems, collaborate with colleagues, attend meetings, learn new skills and adapt to changing priorities.
When every minute of every day is already allocated, there is no capacity left to absorb the inevitable variability of work.
Instead of increasing productivity, full utilisation creates congestion.
Why busy teams deliver slower
This may seem counterintuitive.
If every person is fully occupied, surely more work gets completed?
Unfortunately, knowledge work doesn’t behave like a factory assembly line.
When teams have too much work in progress, several things begin to happen:
- More work waits in queues.
- People switch between multiple priorities.
- Dependencies increase.
- Decisions take longer.
- Defects increase.
- Delivery slows.
The irony is striking:
The busier an organisation becomes, the less efficiently work flows.
This principle is well established in operations management and queuing theory.
Queuing theory in simple terms
Think about the queue at your local supermarket. When only a few customers are waiting, everyone gets served quickly. As more customers join the queue, waiting times increase. But something interesting happens as the checkout approaches full capacity.
A small delay, perhaps someone searching for their wallet or querying a price, causes waiting times to increase dramatically. The checkout hasn’t become slower. The queue has become longer because there is no spare capacity to absorb normal variation. The same happens inside organisations.
Every new project, urgent request or executive priority joins the queue. When everyone is already fully committed, even small interruptions create disproportionately large delays.
Research in queueing theory consistently shows that as utilisation approaches 100%, average waiting times increase non-linearly—not gradually, but exponentially (Hopp & Spearman, Factory Physics, 4th ed., 2022).
The lesson is simple:
High utilisation does not create high flow.
Slack is not a waste
One of the biggest misconceptions in management is that unused capacity equals wasted capacity. Lean thinking challenges this assumption. Slack is not about people sitting idle.
Slack is the deliberate creation of space that allows organisations to:
- respond to changing customer needs
- solve complex problems
- innovate
- improve processes
- support colleagues
- reduce technical debt
- learn new skills
- handle unexpected work without derailing existing commitments
Without slack, every new request becomes an interruption.
With slack, organisations can adapt without sacrificing delivery.
Toyota understood this decades ago. Lean organisations intentionally create systems that optimise flow rather than maximise individual utilisation.
The goal is not to keep every person busy.
The goal is to help valuable work move through the system quickly and predictably.
Stop measuring busyness
Many leaders still ask questions like:
- “How busy is the team?”
- “Is everyone fully allocated?”
- “Can we fit in one more project?”
These questions focus on activity.
Customers don’t experience activity.
They experience outcomes.
Instead, organisations should ask:
- How long does it take for an idea to reach a customer?
- How predictable is our delivery?
- How much work is currently waiting?
- Where are work items getting stuck?
- How quickly do we recover from changing priorities?
These questions focus on flow.
Agile frameworks emphasise flow-based thinking by encouraging organisations to visualise work, limit work in progress, manage queue lengths and optimise the flow of value rather than simply increasing utilisation.
What leaders should measure instead
If your goal is faster delivery and greater business agility, consider shifting attention from utilisation metrics to flow metrics, including:
- Lead Time – How long does it take from request to delivery?
- Cycle Time – How quickly does work move once it has started?
- Flow Velocity – How much value is delivered over time?
- Flow Efficiency – How much time is spent actively working versus waiting?
- Work in Progress (WIP) – How much work is underway at the same time?
These measures reveal whether your system is delivering value efficiently, not whether people appear busy.
