Argument-based decision support for risk analysis

The calculation of statistical expectation values is a most useful tool in risk analysis, but it is not a panacea. Valuable additional decision support can be obtained from argument-based tools, i.e. rigorous tools based on conceptual distinctions and logical reasoning. If the decision problem is not well defined, then argument-based tools can be used to analyse the uncertainties involved and provide a more well-reasoned presentation of the problem. If the available information is insufficient for a reliable quantitative analysis, then argument-based tools can partly replace it as guidance for the decision-making process. Argument-based tools can be grouped into three main categories: (1) tools used to determine the impact of alternative structurings of decisions and to make an informed choice among them, (2) tools used for the evaluation of decision options, and (3) tools used for the choice among such options in terms of the relative strengths of the arguments that speak for and against each of the options.