Do the simultaneous alignment of student activities (temporal synchronicity) and students successively building on each other's reasoning (transactivity) predict the quality of collaborative learning products? To address this question, we used a mixed-method approach to study 74 first-year university students who were randomly assigned to work in dyads on an ill-defined problem of biodiversity collapse in tropical forests within a computer-supported collaborative learning setting. The quantitative analysis revealed that neither temporal synchronicity nor transactivity was related to the quality of group products. The qualitative analysis of chat transcripts revealed that the variability between the groups could be explained by group dynamics, students' prior knowledge, confidence in managing the learning task, collaborative strategy and communication skills. The study findings could be used to optimize collaboration by informing students directly of their activities or the teachers that scaffold these activities.