Metrics for Application Landscapes

Managing an application landscape has emerged as a new challenge, since the importance, size and complexity of the landscapes is constantly growing in a major share of organizations. This work proposes metrics for application landscapes as a quantitative technique to address the challenge. Its aim is to make application landscape management more systematic and transparent, and render goals and their achievement more accessible to business. This work starts with a broad, general outlook on the subject, followed by a focused treatment of metrics analyzing failure propagation, and concludes with their application in a case study. The first part presents an empirical analysis of the environment, in which metrics for application landscapes are used. In this analysis, expert interviews and an online questionnaire identified application landscape metrics as a relatively young field, however perceived by practitioners as showing considerable potential. Use cases practitioners are especially interested in, include the quality attributes functionality, flexibility, and operational risk. Practitioners intend to use metrics in particular for setting goals, showing the status quo and potential for improvement, as well as communicating facts about an application landscape. In this context, business stakeholders value the ability to communicate the implications of specific structures or changes in an application landscape without delving too deeply into technical details. The analysis results form the basis of guidelines for application landscape metrics. To give an example for application landscape metrics, the second part of the work introduces two methodologies concerned with operational risk: The first one supports analyses of failure propagation in an application landscape, while the second one addresses comparing proposals for limiting failure propagation. Both especially focus on visualizing the metrics they use. In the third part, a case study applies the metrics based methodologies at a large bank, demonstrating their applicability to real world concerns. The case study compares two proposals created by stakeholders for limiting failure propagation. It demonstrates the adaptations necessary to employ the metrics based methodologies in a specific use case. As the case study discusses the prototypical software supporting the necessary calculations, it also contributes to the future development of EA management tools. Altogether, applying the metrics based methodologies provided the stakeholders with an improved insight into the effects connected to their proposals, thus demonstrating the benefit of application landscape metrics.