Description and survey of the possible, guaranteed or offered quality of a service (QoS) is one of the key features to establish a performance and quality oriented assesment or accounting of IT-services. This task is accomplished using various criteria - the so called QoS-characteristics - which, in most cases, are specific to a certain service. From the point of view of the service life cycle, characteristics of a service are evaluated with in the usage phase but are usually determined in the negotiation phase before a service is implemented. The realization of this specifications in the following phases of the service life cycle, service provisioning or implementation and service usage, has not been methodically supported until now and has to be done by hand . Thus, the impact of a specification made in the negotiation phase on the other life cycle phases can only be estimated with expert knowledge. An objective assessment of this impact is impossible. The work presented introduces a technique enabling the formal specification of QoScharacteristics, thus allowing an automatic realization of the specification in the provisioning and usage phase of a service. Until now, only isolated approaches on the specification of QoS-characteristics focusing on specific technologies have been made. In this thesis we present a completely technology independent approach distilled from the typical processes used for measuring QoS in different technologies. In order to implement this idea, a formal model of a common measurement process, based on the MNM service model, is introduced and the specification of a QoScharacteristic is formalized as a refinement of this model. A formal language, capable of facilitating the generation of these models has been developed for this purpose. Consequently, a compiler for this language has been developed to automatically generate a measurement system out of the specification of a QoS-characteristic. This enables the uniform and technology independent specification of QoS-characteristics. In conclusion, a concept for the computer aided specification of QoS-characteristics has been established which, as an audit included in this thesis demonstrates, can be applied to various scenarios in the area of service management. The concept introduced adds quality orientation to existing approaches like CSM (customer service management) and thus paves the way to quality oriented service management.