Impact of role assignment and group size on asynchronous online discussion: An experimental study

Abstract

Role assignment and group size are important design considerations for conducting effective asynchronous online discussion (AOD). While these two design considerations have been investigated separately in literature, few studies have examined their combined effects in AOD. To address this research gap, this study conducted a two-level factorial experiment to determine the main effect and interaction of role assignment and group size on AOD participation, learning experience, and learning achievement. A total of 112 participants from an undergraduate blended course were randomly assigned to four experimental conditions: role-based small-group (n = 27), role-based medium-group (n = 30), role-free small-group (n = 27), and role-free medium-group (n = 28). The ANOVA results showed that the simple role structure of initiator, supporter, and arguer increased the overall participation and peer interaction in AOD, while the group size of three members led to slightly better learning achievement. No significant interaction effects or role-specific effects were identified, indicating that students can benefit from role-based AOD regardless of group size and role script. The study results can inform the design and implementation of effective AOD.