ABSTRACT
This chapter applies the Arrow theorem to decisions based on ranking techniques. It shows that the use of formal and calculative decision-making techniques in planning, necessarily solve the problem of being simultaneously consistent and democratic, which is encountered in dialogical decision-making. Several evaluation techniques for land-use planning and transport planning can handle effects measured on ordinal scales, for example, Lichfield’s community impact evaluation and Hill’s goals achievement matrix. The input to any evaluation technique is information on a set of items, and the set of items handled varies between some of the techniques. The algorithm aggregates subsets of arguments or provides a summation of the entire set, leading to a recommendation of the ‘best’ alternative. Formal evaluation techniques do arithmetically what dialogical decision-making does informally: they reach a reasoned recommendation. The chapter focuses on each of Arrow’s conditions from the perspective of the argumentative interpretation of formal evaluation techniques.
