Measuring students proficiency in MOOCs: multiple attempts extensions for the Rasch model

摘要

Popularity of online courses with open access and unlimited student participation, the so-called massive open online courses (MOOCs), has been growing intensively. Students, professors, and universities have an interest in accurate measures of students' proficiency in MOOCs. However, these measurements face several challenges: (a) assessments are dynamic: items can be added, removed or replaced by a course author at any time; (b) students may be allowed to make several attempts within one assessment; (c) assessments may include an insufficient number of items for accurate individual-level conclusions. Therefore, common psychometric models and techniques of Classical Test Theory (CTT) and Item Response Theory (IRT) do not serve perfectly to measure proficiency. In this study we try to cover this gap and propose cross-classification multilevel logistic extensions of the common IRT model, the Rasch model, aimed at improving the assessment of the student's proficiency by modeling the effect of attempts and by involving non-assessment data such as student's interaction with video lectures and practical tasks. We illustrate these extensions on the logged data from one MOOC and check the quality using a cross-validation procedure on three MOOCs. We found that (a) the performance changes over attempts depend on the student: whereas for some students performance ameliorates, for other students, the performance might deteriorate; (b) similarly, the change over attempts varies over items; (c) student's activity with video lectures and practical tasks are significant predictors of response correctness in a sense of higher activity leads to higher chances of a correct response; (d) overall accuracy of prediction of student's item responses using the extensions is 6% higher than using the traditional Rasch model. In sum, our results show that the approach is an improvement in assessment procedures in MOOCs and could serve as an additional source for accurate conclusions on student's proficiency.