Deriving individual student marks from a tutor’s assessment of group work

The use of group work, in which three or more students jointly produce a piece of work for summative assessment, is an established aspect of teaching and learning in higher education. Opinions vary however about whether their marks should vary according to the respective contributions they made to the work. This paper is based on the assumption that if adjustments are to be made, they should be made on sound statistical grounds. Current methods for adjusting student marks do not allow the size of the adjustments to be controlled and empirical data are presented which show that very large adjustments can occur. This paper presents a method for deriving final student marks from a single tutor mark and ratings which students make of each other’s contributions. The method incorporates a mechanism for directly controlling the size of the adjustments made. It is demonstrated using data from students following a degree programme in computing. A spreadsheet has been written which undertakes the calculations necessary to apply the method.