Quality is a philosophical concept related to how persons, things, facts, activities, conditions and so on are. Quality is not absolute since it depends on values, both individual and shared among groups, communities and societies. Quality is relative since it depends on culture, ethics and civilisation, being linked to time, space and quantity dimensions. Therefore, quality is something difficult to grasp. It should improve, but for every situation to which it is related (persons, products, social communities, etc.) different aspects appear with several combinations. Today there are many approaches to quality and important good practices arise within the mainstream of Total Quality Management (TQM). TQM:

• is a comprehensive approach that involves an organisation to continuously improve its performance over the long term, being customer–focused and meeting the needs of all stakeholders
  
• concerns the system as a an undivided "whole", an organisational complex based on interdependent components (e.g. suppliers, inputs, processes, resources, people, outputs, customers, etc.)
  
• considers the effects of changes on the entire system, not just the individual elements
  
• develops a climate of trust and co-operation among the stakeholders

TQM itself, as a container of concepts aimed at pursuing quality, changes in relation to corporate and community culture. Three basic Japanese terms clearly represent the above assumption:

• Kaizen, as a process of continuous, slow, day-by-day change
  
• Kairyo, as fast, unpredictable modifications and improvement
  
• Kyosei, as an emphasis on social and environmental responsibilities for the present and future generations, as well as equity within world-wide and between local economies
  
  

More recently the concept of total quality environmental management (TQEM) appeared to deal with the links between an organisation and the natural environment, and to foster, especially by adopting life-cycle analysis, ecological performance and clean manufacturing processes which eliminate pollution at the source rather than end-of-pipe.
While ISO 9000 certifications have been created for TQM, those concerning ISO 14001, EMAS and SA 8000 more properly regard TQEM. Their ways to improve quality underline how corporate strategic visions are necessary to promote the principles of sustainable development as a set of core values guiding the firm’s decision-making processes at all levels and fields of activity (e.g. marketing, training, auditing, life cycle of products and processes, etc.).
The quality management approach therefore starts on a meta-level and does not prescribe fixed standards. It deals with the methods and procedures with which quality targets that have been set can be attained or exceeded. The commitment is to ensure optimal and transparent management in the fulfilment of very complex objectives.