"The notion that much of the endeavor of the company that is not quality minded is directed inadvertently to creating waste and performing wasteful tasks – examples of wasteful activities [include] the production of non-conforming products and the holding of excessive stock. The hidden factory is the extra useful, positive output that would theoretically be possible if the energy directed at creating waste were released and directed instead at making good quality items."
Lean refers to "a system of techniques and activities for running a manufacturing or service operation. The techniques and activities differ according to the application at hand but they have the same underlying principle: the elimination of all non-value-adding activities and waste from the business. Lean enterprise extends this concept through the entire value stream or supply chain: The leanest factory cannot achieve its full potential if it has to work with non-lean suppliers and subcontractors." Subsequently, the principles of Lean manufacturing have been applied to other areas such as product development.
"Lean Six Sigma is a process improvement program that combines two ideas: Lean – a collection of techniques for reducing the time needed to provide products or services, and Six Sigma – a collection of techniques for improving the quality of products and services, substantially contributing to increased customer satisfaction. By combining the two, Lean Six Sigma is a proven business management strategy that helps organizations operate more efficiently."
"Six Sigma is a rigorous and a systematic methodology that utilizes information (management by facts) and statistical analysis to measure and improve a company’s operational performance, practices and systems by identifying and preventing defects in manufacturing and service-related processes in order to anticipate and exceed expectations of all stakeholders."
Total Quality Management "describes a management approach to long-term success through customer satisfaction. In a TQM effort, all members of an organization participate in improving processes, products, services, and the culture in which they work. The methods for implementing this approach come from the teachings of such quality leaders as Philip B. Crosby, W. Edwards Deming, Armand V. Feigenbaum, Kaoru Ishikawa, and Joseph M. Juran."