Scripting by assigning roles: Does it improve knowledge construction in asynchronous discussion groups? Tammy Schellens & Hilde Van Keer & Bram De Wever & Martin Valcke Received: 9 June 2006 / Accepted: 10 July 2007 / Published online: 11 September 2007 # International Society of the Learning Sciences, Inc.; Springer Science + Business Media, LLC 2007 Abstract This article describes the impact of learning in asynchronous discussion groups on students’ levels of knowledge construction. A design-based approach enabled the comparison of two successive cohorts of students (N =223 and N =286) participating in discussion groups for one semester. Multilevel analyses were applied to uncover the influence of student, group, and task variables on the one hand, and the specific impact of a particular form of scripting – namely the assignment of roles to group members – on the other. Results indicate that a large part of the overall variability in students’ level of knowledge construction can be attributed to the discussion assignment. More intensive and active individual participation in the discussion groups and adopting a positive attitude towards the learning environment also positively relates to a higher level of student knowledge construction. Task characteristics – differences between the consecutive discussion themes – appeared to significantly affect levels of knowledge construction, although further analysis revealed that these differences largely disappeared after correcting for task complexity. Finally, comparisons between both cohorts revealed that the introduction of student roles led to significantly higher levels of knowledge construction. An effect size of 0.5 was detected. Keywords Asynchronous discussion groups . Computer-supported collaborative learning . Higher education . Online learning . Scripting Introduction Although it has been argued that computer-supported collaborative learning (CSCL) environments foster collaborative knowledge construction (Clark et al. 2003), the major question now is: Under what circumstances, in what particular learning environments, with Computer-Supported Collaborative Learning (2007) 2:225–246 DOI 10.1007/s11412-007-9016-2 T. Schellens (*) : H. Van Keer : B. De Wever : M. Valcke Department of Educational Studies, Faculty of Psychology and Educational Sciences, Ghent University, Henri Dunantlaan 2, 9000 Gent, Belgium e-mail: Tammy.Schellens@UGent.be