Applications

The focusing steps, or this Process of Ongoing Improvement has been applied to Manufacturing, Project Management, Supply Chain / Distribution generated specific solutions. Other tools (mainly the TP) also led to TOC applications in the fields of Marketing and Sales, and Finance. The solution as applied to each of these areas are listed below.

Operations
Within manufacturing operations and operations management, the solution seeks to pull materials through the system, rather than push them into the system. The primary methodology use is Drum-Buffer-Rope (DBR)[3] and a variation called Simplified Drum-Buffer-Rope (S-DBR).

Drum-Buffer-Rope is a manufacturing execution methodology, named for its three components. The drum is the physical constraint of the plant: the work center or machine or operation that limits the ability of the entire system to produce more. The rest of the plant follows the beat of the drum. They make sure the drum has work and that anything the drum has processed does not get wasted.

The buffer protects the drum, so that it always has work flowing to it. Buffers in DBR have time as their unit of measure, rather than quantity of material. This makes the priority system operate strictly based on the time an order is expected to be at the drum. Traditional DBR usually calls for buffers at several points in the system: the constraint, synchronization points and at shipping. S-DBR has a buffer at shipping and manages the flow of work across the drum through a load planning mechanism.

The rope is the work release mechanism for the plant. Only a "buffer time" before an order is due does it get released into the plant. Pulling work into the system earlier than a buffer time guarantees high work-in-process and slows down the entire system.

Supply chain / logistics
Please help improve this article by expanding it. Further information might be found on the talk page. (January 2009)

The solution for supply chain is to move to a replenishment to consumption model, rather than a forecast model.

TOC-Distribution
TOC-VMI (vendor managed inventory)
[edit] Finance and accounting
The solution for finance and accounting is to apply holistic thinking to the finance application. This has been termed throughput accounting.[5] Throughput accounting suggests that one examine the impact of investments and operational changes in terms of the impact on the throughput of the business. It is an alternative to cost accounting.

The primary measures for a TOC view of finance and accounting are: Throughput (T), Operating Expense (OE) and Investment (I). Throughput is calculated from Sales (S) - Totally Variable Cost (TVC). Totally Variable Cost usually considers the cost of raw materials that go into creating the item sold.

Project management
Critical Chain Project Management (CCPM) is utilized in this area.[6] CCPM is based on the idea that all projects look like A-plants: all activities converge to a final deliverable. As such, to protect the project, there must be internal buffers to protect synchronization points and a final project buffer to protect the overall project.

Marketing and sales
While originally focused on manufacturing and logistics, TOC has expanded lately into sales management and marketing. Its role is explicitly acknowledged in the field of sales process engineering. For effective sales management one can apply Drum Buffer Rope to the sales process similar to the way it is applied to operations (see Reengineering the Sales Process book reference below). This technique is appropriate when your constraint is in the sales process itself or you just want an effective sales management technique and includes the topics of funnel management and conversion rates.

The TOC thinking processes
Main article: Thinking Processes (Theory of Constraints)
The Thinking Processes are a set of tools to help managers walk through the steps of initiating and implementing a project. When used in a logical flow, the Thinking Processes help walk through a buy-in process:

Gain agreement on the problem
Gain agreement on the direction for a solution
Gain agreement that the solution solves the problem
Agree to overcome any potential negative ramifications
Agree to overcome any obstacles to implementation
TOC practitioners sometimes refer to these in the negative as working through layers of resistance to a change.

Recently, the Current Reality Tree (CRT) and Future Reality Tree (FRT) have been applied to an argumentative academic paper .

Development and practice
TOC was initiated by Dr. Eliyahu M. Goldratt, being still the main driving force behind the development and practice of TOC. There is a network of individuals and small companies loosely coupled as practitioners around the world. TOC is sometimes referred to as "Constraint Management". TOC is a large body of knowledge with a strong guiding philosophy of growth.

Criticism
Criticisms that have been leveled against TOC include:

It isn't part of mainstream business education
While TOC has applications in TOC factory operations, project management, and supply chain, TOC is not part of the mainstream curriculum in business or Operations Research programs. Thus it must not be a valid technique. D. Trietsch argues that much of TOC is based on previous academic knowledge and complains that Goldratt and the TOC community do not do enough to acknowledge this legacy.

Rebuttal: TOC is an element of many business school education programs, most often with The Goal being required reading. That said, it isn't clear whether the business school programs do anything with the information contained in The Goal and other TOC literature.

Rebuttal Also: For a technique to be valid does not mean that it needs to be in the mainstream curriculum. It just needs to be valid and that should be proven based on it's results not academia.

Effectiveness of Drum-Buffer-Rope
While TOC has been compared favorably to linear programming techniques, D. Trietsch from University of Auckland argues that DBR methodology is inferior to competing methodologies.

Unacknowledged debt
Duncan (as cited by Steyn) says that TOC borrows heavily from systems dynamics developed by Forrester in the 1950s and from statistical process control which dates back to World War II. And Noreen Smith and Mackey, in their independent report on TOC, point out that several key concepts in TOC "have been topics in management accounting textbooks for decades."

People claim Goldratt's books fail to acknowledge that TOC borrows from more than 40 years of previous Management Science research and practice, particularly from PERT/CPM and JIT. A rebuttal to these criticisms is offered in Goldratt's "What is the Theory of Constraints and How Should it be Implemented?", and in his audio program, "Beyond The Goal". In these, Goldratt discusses the history of disciplinary sciences, compares the strengths and weaknesses of the various disciplines, and acknowledges the sources of information and inspiration for the Thinking Processes and Critical Chain methodologies. Articles published in the now-defunct Journal of Theory of Constraints referenced foundational materials. Goldratt published an article[citation needed] and gave talks with the title "Standing on the Shoulders of Giants" in which he gives credit for many of the core ideas of Theory of Constraints. Goldratt has sought many times to show the correlation between various improvement methods. However, many Goldratt adherents often denigrate other methodologies as inferior to TOC.