Today we launch a series of posts on the politics of data. Big data, small data and data sharing will be critically examined by a range of experts, each exploring the implications of the changing data landscape for research and society. In the first piece, Sabina Leonelli and Louise Bezuidenhout argue the study of data itself is an excellent entry point to reflect on the activities and claims associated to the idea of scientific knowledge. How scientists perceive their research environments, what they recognize as strengths and limitations, and what in these environments pose material or social challenges to data engagement all influence how data travels