Comparing the effect of task sequencing, text modeling, and task repetition in the development of L2 writing complexity

This study examines the effects of task sequencing (TS), text modeling (TM), and task repetition (TR) on the syntactic and lexical complexity in second language (L2) writing. While these interventions are individually recognized, research is limited on their impact on longitudinal complexity increase as well as the direct comparison between the three interventions. We collected data from 120 advanced ESL undergraduates, randomly assigned to TS, TM, or TR groups. The TS group completed three versions of an argumentative task with increasing complexity levels over three weeks. The TM group compared model texts to their initial essays before repeating the task. The TR group performed and repeated the task twice. Results showed that while all three interventions led to significant improvements, TS often showed the largest improvement in terms of magnitude, and TR had the most limited improvements, while TM often showed an intermediate pattern, i.e., TS ≥ TM ≥ TR. Correlation analyses showed that syntactic and lexical complexity improved simultaneously in the TS and TM groups, but not in the TR group, suggesting the three interventions tap into different learning mechanisms in L2 writing acquisition.