Quality assurance, as supporting discipline in the assurance of system effectiveness, has now become an integral part of the planning, realization and utilization phases of a product. It ensures that the requirements of the market with respect to quality, reliability, safety and availability are met. It is based on systematic prevention of errors and failures in all phases of the product's life cycle. The term 'system effectiveness' is defined and the quality assurance concept of the Brown Boveri Electronics Division is presented.