Measurement and Fuzzy Scales

Concept measurement presents several difficulties and the tools used to collect qualitative ordinal variables are not always satisfactory. The Likert scale is examined in the context of student evaluation of teaching activity and the measurement approach considers the possibility to apply the fuzzy inference system method to obtain individual values being near the reality and coherent with the prescriptions of the measurement process. The paper presents the results of a survey carried out in the Faculty of Economics at the University of Modena and Reggio Emilia to ascertain the differences between two scales (options): one proposed by the Italian Committee for University System Evaluation (Comitato nazionale per la valutazione del sistema universitario) and another one corresponding to the traditional marks used in the evaluation of student performances in the schools attended before the university (mark scale). The results showed that the latter seemed more coherent with the score (in the decimal scale) assigned to the modalities of the scale.