In the years since the emergence of federal funding agency data management and sharing requirements (http://datasharing.sparcopen.org/data), research data services (RDS) have expanded to dozens of academic libraries in the United States. As these services have matured, service providers have begun to assess them. Given a lack of practical guidance in the literature, we seek to begin the discussion with several case studies and an exploration of four approaches suitable to assessing these emerging services. This article examines five case studies that vary by staffing, drivers, and institutional context in order to begin a practice-oriented conversation about how to evaluate and assess research data services in academic libraries. The case studies highlight some commonly discussed challenges, including insufficient training and resources, competing demands for evaluation efforts, and the tension between evidence that can be easily gathered and that which addresses our most important questions. We explore reflective practice, formative evaluation, developmental evaluation, and evidence-based library and information practice for ideas to advance practice. Data specialists engaged in providing research data services need strategies and tools with which to make decisions about their services. These range from identifying stakeholder needs to refining existing services to determining when to extend and discontinue declining services. While the landscape of research data services is broad and diverse, there are common needs that we can address as a community. To that end, we have created a community-owned space to facilitate the exchange of knowledge and existing resources.