Measurement and classification of inter-actor dependencies in goal models

Goal-oriented requirements engineering approaches aim to capture desired goals and strategies of relevant stakeholders during early requirements engineering stages, using goal models. Socio-technical systems (STSs) involve a rich interplay of human actors (traditional stakeholders, described as actors in goal models) and technical systems. Actors may depend on each other for goals to be achieved, activities to be performed, and resources to be supplied. These dependencies create new opportunities by extending actors’ capabilities but may make the actor vulnerable if the dependee fails to deliver the dependum (knowingly or unintentionally). This paper proposes a novel quantitative metric, called Actor Interaction Metric (AIM), to measure inter-actor dependencies in Goal-oriented Requirements Language (GRL) models. The metric is used to categorize inter-actor dependencies into positive (beneficial), negative (harmful), and neutral (no impact). Furthermore, the AIM metric is used to identify the most harmful/beneficial dependency for each actor. The proposed approach is implemented in a tool targeting the textual GRL language, part of the User Requirements Notation (URN) standard. We evaluate experimentally our approach using 13 GRL models, with positive results on applicability and scalability.