Theory of Constraints (TOC)
TOC, from Eliyahu Goldratt (popularised by the novel The Goal), holds that every system has at least one constraint that limits its output, so improving anything else does not raise throughput. A constraint is any element that limits performance relative to the system’s goal.
Five focusing steps
- Identify the constraint.
- Exploit it: get the most out of it as it is.
- Subordinate everything else to that decision (other steps feed only what the constraint can use).
- Elevate it: add capacity only if exploiting was not enough.
- Repeat: the constraint will move; go back to step 1.
Drum-buffer-rope is the scheduling application: the constraint sets the pace (drum), a buffer of work sits ahead of it, and a rope limits how much work enters the system.
In business processes
The bottleneck is often an approval, a single expert or a shared system. process-mining shows where cases wait; a value-stream map shows where time is lost. TOC then says: fix that step first. It complements lean (flow) and six-sigma-and-dmaic (variation) and shares Lean’s habit of looking at the whole system (about-systems-thinking).
Related
kaizen, BPM hub, bpm-lifecycle
Open items
- Details of the “rope” were drawn from secondary sources; check Goldratt’s own texts before teaching DBR.
Sources
- Goldratt, The Goal, North River Press (first published 1984)
- PMI, comparison of drum-buffer-rope and critical chain buffering: https://www.pmi.org/learning/library/drum-buffer-rope-critical-chain-buffering-8526
- Goldratt Group: https://toc-goldratt.com/