Fuzziness and bias in decision-making processes using an arithmetic mean criterion

Grade averaging (by arithmetic mean) is often performed as an attempt to assess overall student performance. In the case of grade comparison originating in non-equivalent scales, rank errors and absurd averaging may result. As averages are sometimes used for candidate selection, the paper dicusses how decisions based on arithmetic mean interpretation may be true, false, or fuzzy, according to different categories of participating candidates. A two stage selection process is analyzed from the perspective of candidate categories. The impact of the choice of asessment scale on the decision-making process is also evaluated and statistical biases are identified. The relevance of using a uniformity criterion is demonstrated.