Theory of Constraints

A five-step method for improving the whole system.

Eliyahu Goldratt’s Theory of Constraints focuses improvement on what currently limits the system’s goal. Making every team busier is not the same as helping more useful work reach completion.

Start with Constraints and bottlenecks if you need help finding the likely limit. Then use the five focusing steps below.

The five focusing steps

  1. Identify the constraint. Agree the goal and investigate what currently limits it. Use observations and data; do not assume the busiest person or largest queue is the answer.
  2. Exploit the constraint—make best use of it. Reduce avoidable downtime, missing inputs and unnecessary work before buying more capacity. Protect quality, safety and sustainable workloads.
  3. Subordinate—organise other work to support it. Coordinate priorities, handovers and the release of work so the constraint is neither starved nor overwhelmed. Maximum activity everywhere can create more unfinished work.
  4. Elevate the constraint—expand or change it. If the result is still insufficient, consider added capacity, a changed rule or a redesigned process. Check what resources and authority are needed.
  5. Repeat. Check the result and identify what now limits progress. Do not let old policies or habits keep attention on yesterday’s constraint.

Judge the system result

In a service, look at useful work completed to the required standard, total waiting time and quality—not just utilisation at individual steps. Monitor workload and safety so an apparent gain does not transfer harm elsewhere.

A non-constraint improvement may not increase overall output now, but can still have worthwhile quality, safety or resilience benefits. Real systems can also have interacting or shifting limits; use the five steps as a focusing discipline, not proof that there is always one obvious bottleneck.

Source and further reading

Goldratt, E. M. and Cox, J. The Goal: A Process of Ongoing Improvement. North River Press, 1984; revised editions develop the five focusing steps.

The explanations above adapt the method to service improvement; they are not quotations.

What’s your next useful question?

Are we supporting the constraint—or maximising activity around it?

Find the current constraint →
Return to Right problem? →