Risk-based regulation has grown rapidly as a component of Government decision making, andas such, the need for an established evidence-based framework for decisions about risk hasbecome the new mantra. However, the process of brokering scientific evidence is poorlyunderstood and there is a need to improve the transparency of this brokering process anddecisions made. This thesis attempts to achieve this by using agent-based simulation to modelthe influence that power structures and participating personalities has on the brokering ofevidence and thereby the confidence-building exercise that characterises risk-based regulation. As a prerequisite to the adoption of agent-based techniques for simulating decisions underuncertainty, this thesis provides a critical review of the influence power structure andpersonality have on the brokering of scientific evidence that informs risk decisions. Three casestudies, each representing a different perspective on risk-based regulation are presented: nuclearwaste disposal, the disposal of avian-influenza infected animal carcases and the reduction ofdietary salt intake. Semi-structured interviews were conducted with an expert from each casestudy, and the logical sequence in which decisions were made was mapped out and used toinform the development of an agent-based simulation model. The developed agent-based model was designed to capture the character of the brokeringprocess by transparently setting out how evidence is transmitted from the provider of evidenceto the final decision maker. It comprises of two agents, a recipient and provider of evidence, anddraws upon a historic knowledge base to permit the user to vary components of the interactingagents and of the decision-making procedure, demonstrating the influence that power structureand personality has on agent receptivity and the confidence attached to a number of differentlines of evidence. This is a novel step forward because it goes beyond the scope of current riskmanagement frameworks, for example, permitting the user to explore the influence thatparticipants have in weighing and strengthening different lines of evidence and the impact thishas on the final decision outcome.