The data were collected in relation to the following goals: The research was designed to identify some of the key factors driving assessments of the legitimacy of decision-making agencies. The research was based on a set of (vignette-based) experiments that allowed the researchers to identify the effects on legitimacy of various aspects of decision-making responsiveness. Participants (N=438) were drawn from Prolific Academic, and completed an online survey fielded on Qualtrics. Assignment to treatment groups was randomised.