Inhaltsangabe:Abstract: Services in the field of information technology (IT) are an emerging and expanding market. The quality with which they are delivered to the customer and the effectiveness of their provision determine the economic success of an enterprise to a large extent. Therefore, the dissertation centers around service quality and organizational effectiveness. Introducing, the characteristics of services in general - intangibility, inseparability, heterogeneity, and perishability - and the rote of projects in IT services are explained. Then, organizational effectiveness is defined as internal efficiency plus adaptability to external demands. Two models are compared showing that organizational effectiveness consists of several factors - e.g. motivation, management leadership, or structure - which indeed can be measured via a particular diagnosis questionnaire. Analogously, two service quality models are put forth. They reveal that total quality is comprised of the technical quality of the service outcome (objective quality) and the functional quality of the process (subjective quality). Likewise, service quality can be evaluated by regarding ten determinants and graphically displaying them in an importance-performance grid. Relating to both points above, aspects in marketing (internal, interactive) and operations (service as a basic function and as one objective) are considered. The so-gained theoretical insights are practically applied in an investigation of an IT ...