Modification of Scoring Schemes Using Decomposition Procedures on Statistical Data

Abstract

This paper presents a method of modifying original scores to obtain independent random variables. It includes an analysis of the consequences of using such a method. The paper also describes the mathematical background of the method in detail and discusses the possible use of the method in identifying student or participant assessments that are over-or underrated. The method distinguishes performances of students and assesses their written solutions using a scoring scheme. In this study, it is used to analyze the competence of participants in the Physics Olympiad competition. Scoring schemes that are appropriately set by an author for a physics problem present the participant scores as independent random variables. The assessment solutions are analyzed using analytical tools (such as covariant matrix) for the dependence of random variables. The evaluators of the participants' solutions were highly qualified professionals. Nevertheless, the study found statistical evidence of minor distortion in the evaluations, though this was found to only marginally affected the ranking of participants.