Abstract:
This quasi-experimental study investigated the effects of the Task-Based Method of Instruction (TBM) on undergraduate learners’ performance, motivation, and self-efficacy in paragraph writing. An interrupted time series design was employed to track changes in learners' outcomes before and after the intervention. The study utilized a single treatment group, and data were analyzed using a parallel mixed-method approach within the post-positivism paradigm. Data collection involved pre- and post-test assessments to measure learners’ performance in para-graph writing; motivation and self-efficacy writing scale questionnaires, semi-structured fo-cused-group interviews (FGI) to explore participants’ perceptions, challenges, and strategies, and document analysis of learners’ written samples throughout the study. Parametric tests were applied to analyze normally distributed data, with paired sample t-tests determining the statistical significance of differences between pretest and posttest scores. The results indicated significant improvements in participants' performance, motivation, and self-efficacy. The paired sample t-test revealed a significant increase in average scores from pretest (M = 12.75, SD = 1.618) to posttest (M = 16.70, SD = 1.433), with a mean difference of -3.950 (SD = 1.572), t (19) = -11.238, p = .000. A 95% confidence interval ranged from -4.686 to -3.214.Fur-ther analysis using repeated measures ANOVA with Bonferroni adjustments highlighted sig-nificant differences among post-treatment variables, with mean scores and standard deviations as follows: PostGRAavg1 (M = 4.25, SD = 0.287), PostCCavg2 (M = 4.45, SD = 0.302), Post-LeReavg3 (M = 4.35, SD = 0.330), and PostTAavg4 (M = 3.43, SD = 0.442). PostCCavg2 exhibited the highest mean score, while PostTAavg4 was the lowest, reflecting variability in treatment effects across measures. Findings demonstrated a substantial improvement in stu-dents' motivation and self-efficacy post-treatment, affirming the effectiveness of the task-based method in enhancing paragraph writing skills. Pre-intervention, learners struggled with task-based methods, showing poor performance, low motivation, and misconceptions about writing tasks. Post-intervention, participants exhibited noticeable gains in writing performance, moti-vation, and self-efficacy. The study concludes that task-based writing instruction is an effective approach for improving writing skills in EFL learners. Despite challenges in EFL contexts, the integration of task-based methods and existing linguistic resources offers significant benefits. Active engagement with task-based instruction is essential for learners’ success
