Improving University Students’ Argumentative Text Writing Skills through the Collaborative Learning Model

Although collaborative learning has been widely examined in language education, evidence concerning argumentative writing in compulsory Indonesian language courses for non-language majors remains limited. This study examined changes in university students’ argumentative writing performance following a collaborative learning intervention. A quantitative approach with a pre-experimental one-group pretest–posttest design was employed, involving 38 first-year Mathematics Education students selected through cluster random sampling from three classes. Data were collected using argumentative writing tests administered before and after the intervention. Scores were analyzed using descriptive statistics, the Shapiro–Wilk test, a paired-samples t test, normalized gain (N-gain), and Cohen’s d_z. The mean score increased from 60.66 (SD = 7.67) to 88.00 (SD = 5.64), with a statistically significant difference, t(37) = 18.41, p < .001, and a large within-group effect size (d_z = 2.99). The mean N-gain was 0.685, classified as moderate, while the proportion of students meeting the mastery criterion increased from 5.3% to 97.4%. These findings indicate improved argumentative writing performance following the intervention and extend evidence on collaborative writing to a national-language general education context. The results are consistent with social-constructivist accounts emphasizing structured peer interaction in argument construction and offer practical guidance for lecturers designing collaborative writing tasks. Further research should employ controlled designs and examine individual dimensions of argumentative writing to assess the intervention’s contribution more rigorously.