eng Science and Education Publishing American Journal of Educational Research 2333-4770 2014-12-01 2 12 1144 1150 10.12691/education-2-12-3 EDUCATION20142123 article Michael Gr. Voskoglou mvosk@hol.gr 1 School of Technological Applications, Graduate Technological Educational Institute (T. E. I.) of Western Greece, Patras, Greece Fuzzy logic due to its nature of characterizing each case with multiple values offers a rich field of resources covering the assessment of situations characterized by a degree of vagueness and/or uncertainty. In this paper, we apply a new trapezoidal fuzzy assessment model (TRFAM) for measuring students' mathematical modeling (MM) skills. TRFAM is actually a variation of the commonly used in fuzzy logic centre of gravity (COG) defuzzification technique, which we have properly adapted and utilized in earlier papers as an assessment model. Our COG and TRFAM models focus on students' quality performance by assigning greater coefficients to the higher scores. A classroom experiment is also presented, illustrating our results in practice. Through this experiment the above two models are compared to each other and also with two traditional assessment methods based on principles of bivalent logic (the calculation of means and of the GPA index) and some useful conclusions are drawn. http://pubs.sciepub.com/education/2/12/3/education-2-12-3.pdf mathematical modeling (MM) fuzzy sets and logic centre of gravity (COG) defuzzification technique trapezoidal fuzzy assessment model (TRFAM)