This study aims to determine the results of the development of teaching materials of writing esksposition text based problems on X grade students State Vocational School 7 Medan. The research method used is research and development (R & D) method proposed by Sugiyono to refer to Borg & Gall model. The trial subjects consisted of 3 students with individual trials, 9 students with small group trials, and 32 students with limited field trials. Data collection techniques use observation, interviews, questionnaires and exposition writing test. The results show that: (1) validation of material experts includes the expediency of the content with an average of 85.93% on very good criteria, the expediency of presentation with an average of 84.61 % on very good criteria, and language aspects with an average of 88.46% on very good criteria, (2) design expert validation is with an average of 84.58% on very good criteria, (3) teacher’s response is with average 83.82% on very good criteria, (4) individual trial is with an average of 76.39% on good criterion, (5) small group trials is with an average of 81.25% on very good criteria, and (6) ) limited field test is with an average of 87.04% on very good criteria. The writing test result of the exposition text of the students before using the module is 70, while the writing test result of exposition text of the students after using the module increases 84.68. The difference is 14.68 from before to after. This proves that the teaching materials of writing exposition text developed to improve student learning outcomes by using problem-based learning methods.
Keywords: Exposition Text, Modules, Problem-Based Learning, Teaching Materials
