Theory of constraints
Theory of constraints is Eli Goldratt's management methodology built on the observation that every system has one constraint (bottleneck) that limits its total throughput — and the only improvement that increases throughput is the one that elevates the constraint. Improvements elsewhere look productive but don't move the system-level output.
TOC's five focusing steps: identify the constraint, exploit it (run it at maximum effectiveness), subordinate everything else to it, elevate it (add capacity), repeat once the constraint moves. The methodology is foundational to Lean and to The Phoenix Project's framing of DevOps. The hardest discipline is subordination: telling non-constraint steps to slow down or stop when the constraint is full feels counterintuitive but prevents pile-up. The constraint is usually visible only after diagnosis — the team's assumed constraint is often not the real constraint, and chasing the wrong one produces no system-level improvement.
Related terms
- Process bottleneck
A process bottleneck is the step in a workflow with the lowest throughput — the constraint that limits the entire process's output.
- Takt time
Takt time is the rate at which a process must produce output to meet demand — calculated as available production time divided by customer demand in that time.
- Value stream mapping
Value stream mapping is the Lean technique of drawing a current-state diagram of a process — every step, every queue, every handoff, with cycle time and wait time labelled — to identify where value is being added and where it's not.