TQM is mainly concerned with continuous improvement in all work, from high level strategic planning and decision-making, to detailed execution of work elements on the shop floor. It stems from the belief that mistakes can be avoided and defects can be prevented. It leads to continuously improving results, in all aspects of work, as a result of continuously improving capabilities, people, processes, and technology and machine capabilities.

Continuous improvement must deal not only with improving results, but more importantly with improving capabilities to produce better results in the future. The five major areas of focus for capability improvement are demand generation, supply generation, technology, operations and people capability.

A central principle of TQM is that mistakes may be made by people, but most of them are caused, or at least permitted, by faulty systems and processes. This means that the root cause of such mistakes can be identified and eliminated, and repetition can be prevented by changing the process.

There are three major mechanisms of prevention:

1. Preventing mistakes (defects) from occurring (Mistake - proofing or Poka-Yoke).
2. Where mistakes can't be absolutely prevented, detecting them early to prevent them being passed down the value added chain (Inspection at source or by the next operation).
3. Where mistakes recur, stopping production until the process can be corrected, to prevent the production of more defects. (Stop in time).

The basis for TQM implementation is the establishment of a quality management system which involves the organizational structure, responsibilities, procedures and processes. The most frequently used guidelines for quality management systems are the ISO 9000 international standards, which emphasize the establishment of a well- documented, standardized quality system. The role of the ISO 9000 standards within the TQM circle of continuous improvement is presented in the following figure.

Continuous improvement is a circular process that links the diagnostic, planning, implementation and evaluation phases. Within this circular process, the ISO 9000 standards are commonly applied in the implementation phase. An ISO 9000 quality system also requires the establishment of procedures that standardize the way an organization handles the diagnostic and evaluation phases. However, the ISO 9000 standards do not prescribe particular quality management techniques or quality-control methods. Because it is a generic organizational standard, ISO 9000 does not define quality or provide any specifications of products or processes. ISO 9000 certification only assures that the organization has in place a well-operated quality system that conforms to the ISO 9000 standards. Consequently, an organization may be certified but still manufacture poor-quality products.