Independent agencies, credible policies? The role of prior beliefs in shaping stakeholder perceptions of credibility in a contested environment

Agency independence is understood to instil credibility in regulatory policy. This is a core tenet of regulation theory, foundational to the EU regulatory state's own origin story. We put the assumption to rigorous testing, in addition to expanding on it theoretically. We expect that stakeholder perceptions of credibility depend not only on agencies' institutional insulation, but also on whether regulatory outcomes are congruent with stakeholders' prior beliefs and preferences. Focusing on EU food safety regulation and the European Food Safety Authority, we test, observationally and experimentally, whether the credibility of agency scientific outputs is enhanced when stakeholders perceive the agency as more independent. Some support for the theorised link is present observationally, yet we do not find consistent and reliable experimental causal evidence for the purported relationship. We further find that the credibility of agency outputs is greatly influenced by stakeholders' prior positions on the issue, pointing at persistent contestation. The study advances our understanding of the factors that shape credibility perceptions, supplementing institutional accounts with individual-level considerations, namely the role of priors. Our study indicates independence is a necessary but partial solution in that it can enhance stakeholder perceptions of credibility but does not compensate for the negative effect of priors.