Theory of constraints

The theory of constraints is a disciplined way to improve a system by finding the factor that most limits its performance and concentrating action there. Instead of optimizing every activity independently, it asks which constraint governs the output of the whole system.

When to use it

• Diagnose the bottleneck limiting a production, service or administrative process.
• Decide where operational improvement will create the greatest system-wide benefit.

Origins

Eliyahu M. Goldratt introduced the term “theory of constraints” in 1984 through his business novel The Goal. Its logic has deeper roots in production management: Ford’s assembly-line methods, later just-in-time manufacturing and the established practice of “balancing the line” all focused attention on flow and bottlenecks. The model also reflects systems thinking, particularly the insight that interacting parts and feedback loops make the performance of a whole system different from the sum of its local results. Goldratt turned these related ideas into an explicit managerial method centred on the system’s limiting factor.

What it is

An organisation converts resources into products or services through connected activities. At least one factor limits how much value that system can produce. The constraint may be physical, such as a machine, scarce skill or delayed component; managerial, such as a policy or approval rule; or external, such as weak demand or a regulatory limit.

The method deliberately narrows attention. Because only a small number of constraints usually govern overall performance, improving a non-constraint can create activity without increasing output. The useful question is therefore not “Where can we make something faster?” but “What currently prevents the entire system from achieving more of its goal?”