The current study used a scale-based approach and complexity, accuracy, and fluency (CAF) analysis to comprehensively capture the effects of the sociocognitive-transformative approach on 2nd language (L2) learners' writing performance. The study involved 66 preuniversity intermediate L2 students from 4 different English classes. I randomly assigned 2 sections to the control group (N = 31) and the other 2 sections to the treatment group (N = 35). Findings from this pretest-posttest nonequivalent control group design revealed that students who received the treatment significantly improved their writing performance and outperformed the students in the control group. In terms of CAF, findings showed that the treatment group improved their fluency and complexity but not their accuracy. The findings further revealed that the treatment group outperformed the control group in 2 of the 3 components of CAF. I discuss implications for L2 writing pedagogy and future studies.