CF Dictionary · Theory of Constraints Terms
Bottleneck
The slow step that limits the throughput of the whole system. The single constraint to focus on.
Also: constraint, limiting factor
A bottleneck is the slow step in a system that limits the throughput of the whole. Also called a constraint or limiting factor.
Why bottlenecks matter
- They set the pace. No matter how fast other steps are, the bottleneck determines the system's speed.
- They're the place to focus. Improving the bottleneck improves the whole.
- They're usually one. Like a chain with one weakest link, most systems have one bottleneck at a time.
The chain analogy
"If the weakest link will break when the chain is pulled on with 5000 newtons of force, then increasing some other link's capacity from 8000 to 8200 newtons won't make the overall chain stronger."
CF's adoption
CF adopts bottlenecks as central to multi-factor decisions:
- Find the bottleneck. What's the factor nearest its breakpoint?
- Focus there. Don't optimise excess-capacity factors.
- Use buffers to protect the bottleneck from variance.
How to identify a bottleneck
- Observe flow. Where does work pile up?
- Measure utilisation. Which step is at 100%?
- Test perturbations. What happens if this step slows down? If the whole slows, it's the bottleneck.
"Bottlenecks are also called 'constraints' or 'limiting factors'. A bottleneck is the slow part of the system that other stuff has to wait on." — criticalfallibilism.com