Theory of Constraints (TOC) is a popular management methodology developed in the 1980s, Eliyahu Goldratt, which is based on finding and managing key constraint system, which determines the success and effectiveness of the whole system. The main feature of the methodology is that making efforts over the management of a very small number of aspects of the system, an effect much greater than the result of simultaneous action on all or most of the problem areas of the system immediately.
The approach is based on the theory of constraints to identify this limitation and manage to increase the rate of generation of profits. Methodologically theory of constraints includes a number of logical tools to find the limit, reveal behind it administrative contradiction, to find a solution and implement it in the interests of all stakeholders. Focus on the final financial result allows us to achieve quick results for the business (2-3 months), focus on win-win solutions enabling to increase the level of interaction and motivation of staff. The theory is applied in production management, project management (new product development, construction), and procurement and distribution of goods.
Among the proposed methods of the theory of constraints - a set of rules to check the consistency of the allegations of the organization and the causal relationships between them, the algorithms for constructing causal diagrams, the method of "drum - buffer - rope", and critical chain method for project management.
The Method of "Drum - Buffer - Rope"
One of the methods of the theory of constraints, widely used in manufacturing, is the method of "drum - buffer - rope," asked the following principles:
"Drum" - production should work according to a certain rhythm;
"Buffer" - before the restriction must be some buffer stocks of materials, protecting the restriction of downtime;
"Rope" - materials must be submitted in production only when stocks have reached a certain limitation to the minimum, not before, so as not to overload the production.
Classical system Drum-Buffer-Rope is a mechanism for control of industrial processes, aiming at is to "broaden" the restriction of the system to subjugate the entire production the most efficient use of limited. In practice, the construction of such a system includes the development of a detailed work schedule to limit (drums), creating a protective buffer prevents possible idling restrictions (buffer), as well as organizing the timely release mechanism works in production (rope).
It should be noted that the classical mechanism Drum Buffer Rope not always be correctly applied in practice. Most often difficult to observe the correct sequence, where first there is rope, followed by buffer, and the drum is activated only in special cases. Moreover, a significant barrier successful application mechanism is the difficulty in synchronization sales and production process. In this regard, a high enough interest is simple Drum-Buffer-Rope.
Theory of Constraints also offers a more general systematic approach to search and remove the restrictions that can be applied not only in manufacturing but in others, a wide variety of systems. This approach consists of constructing a consistent analytical framework of the following types:
Current Reality Tree (TDR similar to the current state of the chart used by many organizations) is to identify the causal relationship between adverse events and the root causes of most of these adverse events.
Diagram of conflict resolution (DRC) is to eliminate contradictions in the system that often cause unwanted situation in the system. Remedy contradictions is called injection.
Future Reality Tree (FRT) - when selected, some methods (injection) address identified using TDR root causes of problems or conflict diagram conflict resolution, built a tree, showing the future state of the system. It is necessary to identify the negative effects of the selected injection (negative branch) and a choice of ways to combat them.
Tree of transition is to identify possible obstacles to change and correct them.
Transformation plan is to develop specific instructions for contractors to implement the planned changes.
Criteria for Validation of Logical Constructions
The method of thought processes Goldratt, unlike many similar techniques of information visualization (e.g., Ishikawa Diagram, mental maps), offers a set of rules to validate the presence of cause-effect relationships and their reliability. Such rules are called criteria validation of logical constructions (CPLP, Categories of Legitimate Reservation) - the eight provisions, with which you can test to prove or disprove properly structured causality:
Clarity - all clearly understand the statements used in the chart.
Availability approval - approval contains a complete thought.
A causal relationship - whether the cause is called the above effect?
The sufficiency of the reasons given - called reason enough to cause the above result, in the present context.
Check for alternative reasons - cannot be called a reason to be just one of the possible?
Inadmissibility substitution causes a consequence - confused cause and effect.
Search for verification of the investigation - if there is a reason named, then it should be not only the above result, but some other, side, effects (which need not be indicated on the diagram under construction).
The absence of a tautology - a consequence offered as justification for the existence of reasons.
Cox, Jeff; Goldratt, Eliyahu M. (1986). The goal: a process of ongoing improvement. [Great Barrington, MA]: North River Press. ISBN 0-88427-061-0.