Technological advancements in the field of data analytics, algorithms and AI have dramatically increased opportunities for workplace monitoring. In this article, we discuss some of these digital technologies, and examine their impact on employment relationships and the quality of work. Based on desk research, literature review and interviews, the Rathenau Institute examined a wide range of digital instruments, their scientific basis, implications for the quality of work and relevant legal frameworks. Digital monitoring technologies often quantify work activities. We argue that it is important for organisations to realise that such quantification often negatively impacts both job quality and employment relationships. Responsible use of digital monitoring tools not only requires a broad societal and political dialogue about privacy, discrimination and workload but also a critical reflection on the aim of organisations to use data to understand workers, while not everything of value can be captured in data.