摘要：Teaching writing has been challenging for some teachers particularly in the context of teaching English as a Foreign Language. Learners’ problems with regard to vocabulary, grammar, organization, and mechanics are among those which can become the sources of the challenge. For that reason, various teaching strategies have been developed to facilitate learners in improving their writing skills among which include Problem-Based Learning (PBL). This paper investigates the effectiveness of Problem-Based writing instruction on students’ argumentative writing skills with regard to content, organization, vocabulary, grammar, and mechanics. It employs a quasi-experimental study by involving the intermediate level students of Lambung Mangkurat University, a state university in Indonesia as the experimental and the control groups. The instrument is a writing test which is statistically proven to be valid and reliable. The findings show that there is a significant difference in the mean scores of argumentative writing skills of students taught using Problem-Based writing instruction compared to those taught using guided-writing instruction in which the obtained p value is .041 which is less than the α .05 significance level. A significant difference is also found in the components of organization, vocabulary, and grammar. The results confirm that Problem-Based writing instruction can be recommended as an alternative teaching strategy particularly in teaching argumentative essay writing. The study also suggests that further research involves larger samples and the skills in listening, speaking, and reading to establish more conclusive findings on the roles of PBL in English Language Teaching contexts.
关键词：argumentative writing; effect; Indonesian EFL learners; Problem-Based writing instruction
