Consideration of the specific requirements of product-related services are increasingly important when it comes to differentiating companies effectively. This thesis therefore presents a method for analysing requirements that refines the service engineering process, especially with regard to the development of product-related services.

As a starting point, the author investigates the state of the art concerning the characteristics of product-related services, the service development process as a basic framework, the principles of requirements specification as well as existing approaches for requirements analysis. These approaches are analysed in the fields of product, software and service development. In addition, the situation in practice is examined. An empirical study was undertaken to analyse the current situation and the application requirements from a business perspective. The responses from 162 enterprises lead to reliable quantitative results, which were deepened with qualitative information by a workshop with company experts. The investigation revealed significant deficits.

The approach for the requirements analysis procedure is derived from six major demands. It proposes a procedure model for the requirements analysis that describes all the necessary process steps in detail, and in a meaningful order, and integrates suitable methods and tools to support it. The aim is to take account of relevant conditions and constraints, ensure the completeness and consistency of the requirements of internal and external stakeholders and facilitate adequate documentation for the subsequent development process. For this purpose, applicable elements are identified and transferred from product and software development. Remaining gaps are closed by the design of new methods and tools.

The approach is implemented in a configurable procedure model containing modules for the individual activities in the six main steps: definition of skeleton information, identification of requirements, structuring of requirements, transformation into design requirements, documentation of requirements and requirements validation. The complete requirements analysis procedure is modelled as an event-driven process chain (EPC). All necessary activities are therefore determined, defined as modules and arranged in a reasonable workflow according to their logical dependencies. The contents and activities for each step are described together with the supporting methods and tools. The individual design of each process is assisted by a configurator, which asks six questions concerning the most important criteria. Based on the answers provided, the configurator automatically generates a recommended reference process as well as suitable methods and tools.

A master document containing a concise summary of all relevant conditions and constraints is prepared to enable the creation of a defined interface on entering the requirements analysis phase. Checklists for stakeholders and influencing factors are formulated to permit the requirements to be identified and, for example, brand and primary product strategies explicitly integrated. A requirement catalogue for product-related services is developed as an additional instrument to support the completeness of the requirements. A method for determining the expectation profile by means of a self-assessment is designed to facilitate the quantitative specification of the design requirements. Its purpose is to ensure that the performance level is geared to customer expectations. A hierarchical requirements model with three tiers is defined for the set of all requirements and their associated attributes. A requirements list is drawn up in which these requirements and information can be documented transparently for the subsequent development process.

The procedure was implemented in an evaluation project without any problems and proved to be easy to apply. The effort was acceptable in relation to the development process as a whole. A systematic review confirmed that the posted demands are met. In addition, the procedure was assessed by selected experts from a practical perspective. An improvement relative to the status quo was achieved with all criteria; the experts valued the procedure as a significant improvement for half of these criteria.

A methodology is thus available for the requirements analysis which is feasible, comparatively simple to use and produces good results. The higher quality of the requirements leads to a more efficient development process, increased customer satisfaction and loyalty and hence a positive impact on sales and profitability.