Drum-Buffer-Rope (DBR) is eliyahu-goldratt's production scheduling method, designed to operationalize the five-focusing-steps on the shop floor. It provides a concrete mechanism for subordinating the entire production system to the pace of its constraint.
The three elements:
DBR was first described concretely in the-race (1986), co-authored with robert-fox, which presented the underlying production logic in a more structured form than the-goal's narrative. DBR directly challenges the conventional wisdom that every resource should be kept busy — idle non-constraint capacity is often desirable, not wasteful, because excess production simply becomes stranded inventory.
buffer-management is DBR's ongoing monitoring companion: rather than tracking machine utilization, managers watch how buffer levels fluctuate, using buffer penetration as the signal for when to intervene.
A simplified variant, Simplified DBR (S-DBR), was later developed to handle environments where the constraint is the market rather than an internal resource, and was explored by eli-schragenheim and others in the avraham-y-goldratt-institute community.