INTERNATIONAL JOURNAL OF ASSESSMENT TOOLS IN EDUCATION, cilt.5, sa.2, ss.339-369, 2018 (ESCI)
This study is a part of a large scale project in which an action research design is used to teach proof to 11th grade students. This part of the project aims to identify students' comprehension level through five proof comprehension tests developed by the researchers based on the National Geometry Curriculum. Data were analyzed by considering the framework of Yang and Lin's (2008) multilevel model. Results showed none of the students were successful at the most sophisticated level of the proof comprehension tests which requires conducting a proof in various ways or proving different theorems by using the same proof methods. Moreover, the highest proof comprehension was obtained from the level containing knowledge about definition, properties, and meanings of symbols. Achievement and comprehension decreased for components of a proof needing higher level mathematical skills. Based on the study's results, suggestions about teaching proof are provided.