Objective Evaluation of Geometrical Product Specification/Geometrical Dimensioning and Tolerancing Basic Skills

Abstract

The aim of this work is to study methods and criteria to objectively evaluate Geometrical Product Specification (GPS) and Geometrical Dimensioning and tolerances (GD&T) basic skills of engineering students. To do so, it is important to define who is the examiner, what is the topic of the exam, how to examine, when and why. In particular, for what concerns the topics, knowledge, competences, skills, concepts and abilities should be assessed. Basic knowledge is the easier topic to evaluate in an objective and reliable way, for example using closed-ended questions, but skills like creativity are difficult to measure. Following the principles of Bloom’s taxonomy, a technical drawing evaluation grid has been developed and used by the authors. The grid has eight learning levels, and target knowledge, competences, and skills have been defined for each learning level, then specific tests to verify the target for each level have been studied and developed. In this paper some examples of application of the grid are described and some preliminary results and considerations are reported. In particular, using an objective closed-ended question test, which rigorously assesses the basic levels of the grid, “residual” students decrease in number, and the students increase in number, the test is cost-effective.