This paper examines a recent example of evidence-based decision making affecting social policy at the trial court level. It offers a close reading of Carter v Canada (AG), decided by the British Columbia Supreme Court, and of Justice Lynn Smith’s careful scrutiny of the social science evidence when invalidating the Criminal Code prohibition on assistance in dying. Drawing on literature which examines the legal system’s use of social science evidence and expert witnesses, this paper suggests that Justice Smith’s treatment of the evidence in Carter provides an example of skilled judicial treatment of the extensive amounts of social science evidence typically tendered in Charter challenges related to controversial social issues. First, it considers the implications of the Supreme Court of Canada’s revised approach to social fact-finding by trial judges and the consequent need for trial judges to critically evaluate and effectively draw on the social sciences. Second, it examines certain limits to courts’ institutional capacity to evaluate the work of social scientists — specifically, the general lack of judicial training in disciplines other than law — and suggests that the trial judge’s approach in Carter is one to be emulated in future cases with similarly vast evidentiary records. Third, it looks at the role of the expert witness and at some of the dangers inherent in judicial reliance on expert testimony and highlights the ways in which Justice Smith’s careful consideration of the subtle effects of adversarial bias may have affected her approach to the evidence. It suggests that while some judges might struggle with common risks and challenges associated with judicial reliance on this type of evidence in the adjudication of social policy, the trial decision in Carter demonstrates that these difficulties may be overcome.