Table 1 Summary of empirical studies
Authors | Participants & context | Source of feedback | Complexity measure(s) | Key findings |
|---|---|---|---|---|
Eckstein et al. (2020) | 23 international graduate students; US | Teacher | Mean length of sentence, mean length of T-unit, and complex nominals per clause from L2SCA | Timely feedback supports syntactic complexity development |
Eckstein and Bell (2021) | 63 international FYC students; US | Teacher | Mean length of T-unit, ratio per T-unit of clauses, coordinate phrases and complex nominals from L2SCA | Students with dynamic WCF demonstrated significantly less syntactic complexity over time |
Evans et al. (2011) | 30 undergraduate students; US | Teacher | Mean length of T-unit | Negligible effect of dynamic WCF on syntactic complexity |
Fazilatfar et al. (2014) | 30 advanced students from an English institute; Yazd | Teacher | Mean length of sentence and a dependent clause ratio from L2SCA | Unfocused WCF led to gains in syntactic complexity |
Hartshorn et al. (2010) | 47 ESL students; US | Teacher | Mean length of T-unit | Dynamic WCF had slight unfavourable effect on writing complexity |
Hartshorn and Evans (2015) | 27 learners; US | Teacher | Mean length of T-unit Clause to T-unit ratio | No meaningful difference between the control and treatment groups in terms of two complexity indices |
Li et al. (2020) | 66 non-English major freshmen; China | AWE (Pigai) | All indices from L2SCA | Students’ syntactic competences developed in some aspects of syntactic complexity |
Van Beuningen et al. (2012) | 268 students from secondary education; Dutch | Teacher | Number of subordinate clauses per clause | Positive effect of comprehensive error correction on students’ structural complexity |
Xu and Zhang (2021) | 65 sophomores; China | AWE (Pigai) | Number of clauses per T-unit from L2SCA | Syntactic complexity remained unchanged |
Zhang and Cheng (2021) | 72 English major sophomores; China | Teacher | Mean length of T-unit and Ratio of clauses per T-unit from L2SCA | Comprehensive WCF showed no effects on syntactic complexity |