Bottleneck
The single slowest step in a process — the only one where an improvement changes the total output.
A bottleneck is the step in a process that limits everything downstream of it. Work arrives at it faster than it leaves, a queue forms in front of it, and the total output of the whole system equals the output of that one step regardless of how fast everything else runs.
The operational consequence is unintuitive and worth holding onto: improving anything that is not the bottleneck improves nothing. Speeding up an earlier step just makes the queue longer. Speeding up a later one leaves it idle. This is why so many efficiency pushes produce a busier organisation with identical throughput — everyone got faster except the one place it mattered.
Finding it is usually easy and admitting it is not, because in a small business the bottleneck is very often the owner: the approval nobody can give but them, the proposal only they write. Look for the queue. Whatever work is waiting is waiting on something.
Worked: enquiry to proposal takes 6 days, delivery 10, invoicing 1. Delivery is where the team is, so delivery gets optimised down to 8. Nothing changes — 6 days of proposals are still queuing behind one person. Halving the proposal step instead adds roughly four extra projects a quarter with no other change.
Also known as
- constraint
- chokepoint
Relevant for
- Founders
- Improving anything that is not the constraint changes nothing except how busy people look — find the queue first, and expect it to be waiting on you.
- Business owners
- In most practices the bottleneck is the owner's approval; the fix is a written rule that lets someone else say yes, not a faster owner.