Computers are being used in an increasingly wide variety of application areas, and their intended and correct operation is often critical for business success and/or human safety. Developing or selecting high quality systems and products is therefore of prime importance. Comprehensive specification and evaluation of systems and software product quality is a key factor in ensuring adequate quality. This can be achieved by defining appropriate quality characteristics, while taking account of the intended use of the systems and software product. It is important that every relevant system and software product quality characteristic is specified and evaluated, whenever possible using validated or widely accepted measures.