Drum Buffer Rope (DBR) is a planning and scheduling solution derived from the Theory of Constraints (ToC).
The fundamental assumption of DBR is that within any plant there is one or a limited number of scarce resources which control the overall output of that plant. This is the “drum”, which sets the pace for all other resources. In order to maximize the output of the system, planning and execution behaviors are focused on exploiting the drum, protecting it against disruption through the use of “time buffers”, and synchronizing or subordinating all other resources and decisions to the activity of the drum through a mechanism that is akin to a “rope”.
Theory of Constraints uses a 5 step process, called a ‘Process Of On-Going Improvement’ (POOGI), to improve any system. These steps are called the 5 Focusing Steps:
- Step 1. Identify the system’s constraint(s), the drum
- Step 2. Exploit the System’s Constraint(s).
- Step 3. Subordinate everything else to the above decisions.
- Step 4. Elevate the constraint(s). Basically improve the performance of the drum
- Step 5. If in the previous steps a constraint has been removed, go back to step 1 and identify the new bottleneck
The Boy Scout example in The Goal (I already wrote a post long time ago about one of my favorite books!)
A very illustrative example was how the protagonist of the book manages a boy scout outing, especially how to keep the group together while different boys walked at different speeds. The solution was to put the slowest boy scout Herbie at the front, and prohibiting all others from overtaking him. Additionally, he lightens Herbie’s backpack so that he can walk faster.