The significant role of Discourse Analysis in Applied Linguistics research is underestimated and attention is merely paid to grammar and vocabulary in teaching language skills. The purpose of this investigation was to explore, first, how metadiscourse is related to the quality of the texts that students produce, second, whether EFLers benefit from Metadiscourse Markers (MDM) instruction. This quantitative study benefited from the true experimental method of research, namely; two-group pretest-posttest design. Sixty subjects were randomly assigned to two control (CG) and experimental groups (EG) of thirty each. To minimize the initial differences between the groups, a general writing ability pre-test was administered before the treatment. The students in the EG were taught MDM through a process approach, whereas the students in the CG received no instructions about MDM. Finally, the pre- and post-treatment subjects' papers were analyzed to determine whether metadiscourse usage was different and how the Interpersonal, Textual, and Ideational components of the texts in the two groups were influenced.

Here, the purpose was to discover if the students in the EG who benefited from MDM instruction, outperformed the other group. To this end, the pre-test and post-test papers were scored holistically by three experienced teachers of writing, acting as research raters. The high inter-rater reliability confirmed the accuracy of their scores and the statistical analyses indicated that both groups benefited from instruction but the EG benefited more. The students in the EG produced essays that received significantly higher grades than those in the CG. Deep analysis of the students' essays further showed that this improvement can be attributed to the use of MDM which made the text more accommodating to the readers/raters. The results also suggested that teaching students to use metadiscourse markers may be an important way to improve their writing skills.