New Perspectives in Science Education

Assessment is one of the powerful tools that can influence motivation of students. Importance in giving fair and objective feedback can be seen not only during the instruction but especially in those cases when students’ success and ranking depends on scores gained in the competition. Scores for independently scored parts of assessed problems can be considered as random variables. Dependency of scores at Physics Olympiad of Slovak republic was analysed by determining covariance matrix. Scoring scheme, according to which the performance is assessed by scores, is usually proposed by teachers or skilled authors of physics problem. However, it was found out that independency of random variables is not their general feature when scores were analysed. The reason for it could be found from the qualitative analysis of skills needed for successful solution of particular parts. Some skills and knowledge are needed in more than one part giving advantage for those students who have these skills or knowledge. The higher scores, the better performance, is not always true in this case. Therefore, we proposed unambiguous and general procedure to modify scores in order to get independent random variables. Modified scores can be then calibrated according to the aim of assessment – for example to increase the number of successful competition participants to motivate them. The main features of proposed calibration method are expressed and results of its application on statistical data from Physics Olympiad of Slovak republic are presented. This approach can be applied also in the assessment as it is based on statistical analysis of student’ scores.

Keywords: Scoring scheme, Physics Olympiad, Covariance, Decomposition procedure, Motivation;

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