Evaluating Inter-Organizational Relationships (IORs) is important in today’s businesses for increasing competitiveness and business potential. Typically, IORs are measured by high-level Key Performance Indicators (KPIs) such as trust, knowledge sharing, and others. However, these high-level KPIs are difficult to be measured quantitatively. It is therefore difficult to determine IORs and their outcomes since the evaluation of IORs results in a complex and ambiguous task. In this vision paper, the authors propose a set of research questions dealing with measuring and evaluating IORs.