This presentation provides an overview of a recent research project on theory of constraints (TOC) as reported in the scholarly literature. Over the last 30 years there has been much interest and research using Dr Eliyahu M. Goldratt's Theory of Constraints (TOC). TOC has led to dramatic improvements in factories, hospitals, projects, government departments – in fact, it has been applied to almost every area of human endeavour. Because of this wide applicability, papers have been published in a variety of journals, under many different disciplines and application areas.
This research project, which has been supported by grants from the Goldratt Foundation and Victoria University of Wellington, aims to identify, collect, classify, and share existing TOC knowledge as presented in scholarly publications including journal articles and conference proceedings. We have created a TOC online resource, which we hope supports and encourages collaboration between researchers and practitioners in the field and facilitates building upon existing scholarly advances to progress TOC more rapidly. The database is available online at: http://www.victoria.ac.nz/som/research/theory-of-constraints
We divided publications into four major categories: Critical Chain Project Management (CCPM), Thinking Processes, Throughput Accounting, and Operations Management and Supply Chain. In this presentation we will provide an overview of major publication outlets and important trends in each of the above categories.
In addition to developing the database, we are currently in the process of analysing these data in detail and will be discussing operations management category in further detail as follows.
Over 1000 papers were categorised as Operations Management and Supply chain. Papers were then individually analysed using a qualitative research approach. This process went through several iterations of coding and classifying, both manually and using NVivo software. The papers were then divided into two major categories and subcategories as follows.
Methodological improvements include conceptual development, and scheduling algorithms and mathematical development. Papers categorised as conceptual development showcase how various TOC concepts and methods are embraced, critiqued, altered, or enhanced by various scholars within operations management. The analysis also clarifies how TOC has been used in combination with other concepts and methods such as MRP, ERP, JIT, Agile, Lean, CONWIP, Six Sigma, and TQM. Papers categorised as mathematical development used simulation analysis, or various types of algorithms for proposing, comparing, validating particular sequencing and/or scheduling techniques.
- Methodological improvement
- Conceptual development
- Scheduling algorithms/mathematical development
- Service industry
- Supply Chain
The application category includes both reports on actual cases as well exploratory papers examining or suggesting application of TOC to a particular context within manufacturing and service industries. The findings indicate that the majority of application papers (93%) were in the manufacturing context. We will present the distribution of these examples across types of manufacturing, including electronics, automobile, furniture, shipbuilding, and food. The findings also show that the majority of reported applications used 5FS, followed by DBR. Reports of other methods such as SDBR were rare. A summary of performance improvement achieved as a result of using TOC and lessons learned will be presented.
Within the service industry, healthcare was found to be the largest TOC application area. Other application areas were administration and distribution. In service industry, the majority of publications focused on flow and its interpretation for service, while a few extend the boundaries beyond the flow concept, by using Thinking Process tools. The reported performance improvements of TOC application in the service industry have not been as large as the results achieved in manufacturing. Some of the reported reasons for this and how they may be overcome will be discussed.
The presentation provides a valuable summary, for academics and practitioners, of the developing TOC body of knowledge that has been reported in the scholarly literature. The presentation highlights streams of conceptual development in Critical Chain Project Management (CCPM), Thinking Processes, Throughput Accounting, Operations Management, and Supply Chain. Findings from the analysis of articles within the Operations Management stream are described in more depth. We also discuss reports on TOC tools and how they have been expanded by scholars of various disciplines. The presentation offers useful insights from the analysis of this database, to provide platforms for future research.
Dr. Vicky Mabin is a Professor of Management at Victoria Business School, Victoria University of Wellington, NZ, specializing in TOC and the decision sciences. Prior to joining VUW, she worked for NZ’s scientific and industrial research organisation, working as a consultant to business, government and industry on a wide range of strategic and operational problems.
Vicky holds BSc(Hons) and PhD degrees and a Postgraduate Certificate in Higher Education Learning and Teaching. She is certificated in the TOC Thinking Processes, Operations Management and Distribution Management, and an academic Jonah. She is a Fellow of the Operational Research Society (UK) and has held numerous positions with ORSNZ including President, and NZPICS.
She has published widely in books and international journals, co-authored The World of the Theory of Constraints, and the lead chapter on the TOC Thinking Processes in the TOC Handbook, published by McGraw-Hill in 2010, and has given numerous academic and practitioner presentations and workshops. She is leading the team developing the TOC Research Database, has served on the examinations board for TOCICO, and as an editor for the Decision Sciences Journal of Innovative Education, and International Transactions in Operational Research, and for the TOCICO white paper series.