AbstractRegulatory impact assessment (RIA) is an appraisal tool to bring evidence to bear on regulatory decisions. A key property of RIA is that is corrects errors in reasoning by pushing regulators towards deliberative thinking to override intuitive judgments. However, the steps for regulatory analysis suggested by international organisations and governmental handbooks do not handle two sources of bias and barriers that are well documented in the literature on behavioural insights. First, bias enters the process via knowledge production during the analytical process of assessment. Second, bias affects knowledge utilisation when regulators “read” or utilise the results of RIA. We explore these two pathways by focusing on drivers of behaviour rather than lists of biases. The conclusions reflect on the limitations of current practice and its possible improvement, making suggestions for an RIA architecture that is fully informed by behavioural analysis.