Öz
In studies conducted to improve primary school students' writing skills, it has been determined that they make errors in the use of the punctuation marks and do not use spelling rules correctly. The purpose of this study was to reveal the effect of a qualified and planned peer and self-assessment-based editorial study [PSABES] on the success of fourth-grade elementary school students in following spelling rules and using punctuation correctly. In this study, an explanatory mixed design was used, and the research was carried out with 60 fourth-grade students attending a public school in Istanbul during the 2019-2020 academic year. According to the results of the research, it was determined that PSABES was effective in students' performance in adhering to spelling rules and using punctuation correctly. This was due to PSABES’ contribution to creating a positive attitude toward writing, increasing motivation, learning desire and communication skills, and allowing students to gain a culture of criticism, feel more valuable, recognize their mistakes, take responsibility and write more carefully. This research clearly demonstrates the effects of peer and self-assessment on the correct use of spelling rules, and punctuation marks. In subsequent research, the effects of self and peer assessment on students' overall writing success can be examined, and it can also be investigated how this process plays a role in shaping the writer identity of students.