Whenever we hear the term quality we frequently think of the quality of goods and products: They can be of good or first class quality, durable or proven quality. In everyday usage the term quality principally has a positive connotation. Quality is generally a good characteristic. If an item is bad, it has no or insufficient quality. The persons who pass judgment on quality are the users or the customers. Whatever they find useful has quality.

The term quality can be found in different contexts. Amongst other things, it plays a decisive role in the field of industrial production. Here the term has been clearly defined. Quality management, design and project control, tests, corrections etc. are all facets of quality, which within industrial production serve to eliminate production errors before they can occur, thus increasing productivity and competitiveness.

Before discussing the tasks and possible solutions within voice and speech quality research, it is essential to clarify some of the terms involved. One reason for this is that the term quality also occurs in some derivatives such as quality checks, elements of quality, quality features, requirements of quality, planning of quality, product quality, test quality, and/or quality of test implementation. In order to be able to inaugurate these nuances into the field of voice and speech quality assessment, these terms must be given a standard definition. As will later become clear, many of the aspects of the term quality , as they are used in the field of industrial production, are also...