• interpretivism;
  • evidence-based policy;
  • Defra;
  • bureaucracy

The Department of Environment, Food and Rural Affairs (Defra) has been heavily criticised for its handling of disease outbreaks in recent years by analysts who compare the conduct of officials with the model of evidence-based policy making, finding fault in their use of advisers or decision-making processes. In this article, I take an alternative approach to policy analysis, based on ethnographic research in the department. I explore the day-to-day interactions between scientific experts and policy makers in Defra to understand why policy making takes the form it does and how scientists negotiate their position within this process. I argue that policy making in Defra is organised by socially constructed narratives that help officials and advisers to make sense of their roles in the policy-making process. Drawing on insights from organisational sociology, I analyse the ways in which Defra officials talk about their responsibilities and understanding of their roles. These narratives act as ‘modes of ordering’ that bring about organisational realities by structuring their relationships, influencing the way they use scientific advice and consequently affecting policy outcomes. I outline three modes of ordering that can be identified in Defra – rationalism, bureaucracy and expediency – and demonstrate that they correspond to three complementary images of evidence-based policy making.