Protocol
Protect bottleneck capacity from avoidable work
Constraint time should be reserved for work only the constraint can do.
When it fits
- When a constrained specialist spends substantial time on tasks that do not require the constraint's expertise.
When to avoid it
- Queueing equations have specific assumptions. Use them for directional reasoning and measurement design, not as exact forecasts for arbitrary multi-stage knowledge work.
Why it matters
Identify interruptions, rework, setup and low-skill tasks consuming bottleneck capacity; move, automate or prepare them elsewhere where safe.
Steps
- List bottleneck time by activity.
- Mark work that could be done elsewhere.
- Improve input readiness before the constraint.
- Protect focus without hiding real coordination needs.
An example
A scarce architecture reviewer stops formatting documents and receives pre-checked evidence packs, preserving review time for actual architecture decisions.
Check your result
More bottleneck time is spent on unique constraint work without increasing downstream defects.
Keep this limit in mind
- Queueing equations have specific assumptions. Use them for directional reasoning and measurement design, not as exact forecasts for arbitrary multi-stage knowledge work.
Connected ideas
Useful withMove quality checks upstream of the bottleneck
Evidence and sources
Provides context
Kingman's heavy-traffic result underlies a queueing approximation in which waiting increases sharply with utilization and with variability in arrivals and service.
It is a single-server heavy-traffic approximation and should be used as directional intuition, not as an exact prediction for arbitrary multi-stage work.
The Single Server Queue in Heavy Traffic · Research note metadata and established heavy-traffic formulation