TOC (Theory of Constraints)

Abstract

The Theory of Constraints (TOC) was introduced in 1984 by Dr. Eliyahu Goldratt in his bestselling novel « The Goal » [1]. It has been developed continuously since then by Dr. Goldratt as well as other contributors and has become a notable method in the world of management.
This theory is a problem-solving management method. TOC is based on an iterative method for improvement. It considers every system as a chain of activities that operates one after another and hypothesizes that this chain is not stronger than its weakest link. Indeed, among these activities, one acts as a constraint upon the entire system, i.e. the weakest link. These limiting factors or constraints, also referred as bottlenecks, are slowing down the process of a system.
The overall goal is to eliminate these constraints in order to enhance performance. To do so, five steps have been defined as the key steps of all the methods derived from TOC. These Five Focusing Steps are : Identify, Exploit, Subordinate, Elevate and Warning.

The first application of TOC was for manufacturing but it has evolved and is now applicable for any type of project management. Indeed, Looking at manufacturing management, the primary methodology used is the DBR, standing for Drum-Buffer-Rope.
On the other hand, for any type of project management, the Critical Chain Project Management) (CCPM) has been developed.
Nowadays, from a project management perspective, multiple tools derived from the TOC have been developed, also known as Thinking Processes (TP). This set of tools embodies the whole TOC and helps identify and manage constraints in projects.