Abstract

The current  study was aimed to find out whether the developing business letter writing materials through peer editing technique  were valid, practical and had potential effect for the management students of Faculty of Economics at Tridinanti University of Palembang. Developmental research proposed by Akker  i.e analysis, design, evaluation and revision was applied in this study. In the evaluation phase, formative evaluation model proposed by Tressmer was used (i.eself evaluation, expert review, one to one small group and field test). There were 3 students participating in one to one evaluation, 9 students in small group and one class (34 students) i field test. There were also two validators in reviewing the developing business letter writing materials through peer editing technique . One was expert of content and another one was expert in  instructional design. The result of experts judgement showed that the product was valid with average score was 89.2 categorized in good validity. The product was practical with average score in one to one evaluation was 84.3 and in small group phase was 86.8. the effectiveness of the product could be seen from the average score of students’achievement in field test. The score was 92.8 meaning that the score was higher than the criterion of minimal mastery (KKM) of developing business letter writing materials through peer editing technique. Therefore, the product had potential effect categorized in very good level.It could be used for the better improvement and contribution in the field of ESP language teaching and learning.