The Influence of Project-Based Learning Model on Students' Argumentative Writing Ability Controlling for Initial Reading Ability

Abstract

Argumentative writing ability was an essential higher-order thinking skill for high school students. However, the 2023 National Assessment data showed that only 34% of students in Central Java achieved minimum competency. This study aimed to examine the effect of Project-Based Learning (PjBL) on students' argumentative writing ability after controlling for initial reading ability. A quasi-experiment with a pretest-posttest nonequivalent control group design was used. The sample consisted of 128 eleventh-grade students of SMA Negeri 5 Kediri (64 experimental, 64 control) selected by purposive sampling. Instruments included a reading comprehension test (20 items, α=0.88) and an argumentative writing rubric (4 indicators, α=0.91). The experimental group received PjBL for 8 sessions (4 weeks), while the control group received conventional instruction. Data were analyzed using one-way ANCOVA with initial reading ability as a covariate. Results showed that after controlling for initial reading ability, there was a significant difference in argumentative writing ability between the two groups (F=24.56; p<0.001; η²=0.32). The mean posttest score of the experimental group (82.4) was higher than that of the control group (71.6). Initial reading ability contributed significantly (F=18.34; p<0.001; η²=0.13). These findings indicated that PjBL was effective in improving argumentative writing regardless of students' initial reading ability differences.