Abstract. According to modern service science theory, value is jointly generated by several partners forming a service system. In this work, we focus on a simple two-party system consisting of a service provider and its customer. The value created by this service system hinges on the contribution of both parties. That is, it also depends on the collaboration of the customer, which is a key characteristic of services in traditional definitions. Providers, however, lack knowledge on how to identify and measure the influence factors for value cocreation, such as customer contribution. Being aware of customer contribution, providers could design and manage value propositions purposefully. In this work, we provide a first version of a framework of influence factors for value co-creation in service systems, which may serve providers as a guideline for identifying different types of customer contribution.