A Proposal of the Competency-Based Teaching Sequence for Deductive Proofs in Geometry in Secondary Schools

There is still much debate surrounding the development of an effective teaching sequence for deductive proofs in geometry, and no consensus has been reached on which competencies need to be developed and in what order. In this paper, we examine students’ performance in deductive proofs in geometry in order to suggest a hypothetical teaching sequence for these proofs. By analysing survey data from 238 Year 8 and 208 Year 9 students, we found that there were still challenges relating to competencies concerning the generality of proofs, the structure of proofs, the definitions of shapes, and spatial reasoning in order to achieve more successful proofs in geometry. We then constructed a hypothetical teaching sequence based on path analysis and structural equation modelling. Our results provide guidance on the order in which geometry should be taught for deductive proving.