Researchers have made increasing efforts to consider the contexts where evidence is implemented, and more meaningfully include forms of public participation that make science more accountable and responsive to the people and places meant to take it up. The rise of implementation science and hybrid clinical trials are both examples of this contextualization. As the production of evidence moves toward its contextualization and begins to more meaningfully consider the role of the social environment in knowledge making and uptake, novel partnerships and political questions emerge. This dissertation is an ethnographic study of a complex harm reduction and peer recovery-based case management intervention (HaRP). Instead of studying whether and how HaRP works, however, this dissertation examines how researchers and various implementation actors negotiate the tension between conducting experimental science to produce a standardized, scalable intervention, while also being attuned to the “real world” of social service practice. Drawing on over two years of ethnographic field work of a federally funded, multi-sited clinical trial, I ask: how, and with what social effects, do researchers negotiate the principles of scientific inquiry with the exigencies of the “real world,” and the diverse sets of institutional commitments that make it up? Throughout this dissertation, I highlight how local context and scale, objectivity and activism, and standardization and tacit, embodied forms of care are negotiated with experimental logics like standardization, fidelity and objectivity. I argue that the imperatives of the clinical trial, coupled with the institutional obligations to which it is tethered, operate against the ethical and political commitments of practitioners and researchers themselves regarding the most effective strategies for preventing overdose. I show how care is refashioned (Chapter Three), and activism is deferred (Chapter One). However, no one actor had an unwavering commitment to the scientific integrity of the clinical trial and this dissertation set out to reveal how researchers themselves grapple with these tensions. Indeed, Chapter two demonstrates how the imminent needs of study participants led trial actors to compromise model stability and feasibility (Chapter Two). Indeed, experimental concepts like feasibility and fidelity were contested throughout HaRP’s implementation, by PIs and practitioners alike, and were actively redefined to meet the diverse, and often competing nature of hybrid clinical trials. The findings of my dissertation will help researchers, and implementation actors negotiate locally embedded social and professional values and growing activist commitments with the obligations of scientific inquiry during socio-behavioral clinical trials.