Purpose - Most of the proposed decision aid methods provide the user only with a prescriptive approach (quantitative analysis) without any descriptive approach (qualitative analysis). It is therefore not possible to justify and recommend ways of improvement. The purpose of this paper is to introduce visualization techniques to complement prescriptive approaches. Design/methodology/approach - Visual techniques have been developed for the FlowSort sorting method, namely the FS-GAIA and stacked bar diagrams. Findings - It is found that with visual techniques, fine details can be captured, e.g. detection of incomparability (with FS-GAIA) and the composition of a score (with stacked bar diagrams). Research limitations/implications - In the future, it is expected that other multi-criteria decision methods will be complemented by prescriptive approaches. Practical implications - A real case study is introduced in order to illustrate the practicality of the visual techniques. In this paper, the innovation performances of small and medium enterprises from the French Lorraine region are assessed. Social implications - It is expected that the quality of the decisions taken are improved because of being better informed. Originality/value - The paper, using a real case study, provides important new tools to enhance decision quality.