<p>Proponents of evidence-based conservation (EBC) maintain that environmental intervention ought to be based on biodiversity data and data synthesis, instead of relying on unproven theory, individual expertise, and customary practices. This paper analyzes the epistemology of EBC, in which data are bestowed, explicitly or implicitly, with a privileged status and intrinsic evidential significance. I problematize this view by reviewing the complex knowledge infrastructure and dynamics involved in <i>turning</i> data into evidence within biodiversity conservation. Building on the philosophical literature on the nature, journey, and social embeddedness of data, I highlight the critical role of scientific <i>protocols</i> in producing reliable, actionable knowledge for conservation. I argue that protocols are established precisely because data do not have the highest epistemic privilege or intrinsic evidential significance. To illustrate my point, I examine two case studies: the Conservation Evidence project and the Red List of Threatened Species. I discuss some of the conceptual and practical consequences of improving the epistemology of EBC. Furthermore, I show how protocol implementation can generate multiple data communities that are constrained by, yet open to, negotiations regarding evidential standards.</p>