Abstract

• The main purpose of this study was to study the effect of van Hiele’s instructional model on students’ achievement in geometry. This study was conducted with both quantitative and qualitative research methods. For quantitative research, an experimental study was used to study the effect of van Hiele’s instructional model. In this experimental study, the subjects were Grade seven students selected from No. (7), BEMS, Hlaing and No. (9), BEMS, Insein. The experimental designed adopted in this study was a true experimental design, namely, posttest only control group design. For this study, (60) Grade Seven students from No. (7), BEMS, Hlaing and (62) Grade Seven students from No. (9), BEMS, Insein were selected by random sampling method. These students were divided into two groups: control and experimental. The experimental group was treated with van Hiele’s instructional model and the control group was taught with formal instruction. After that, a posttest was administered to two groups. Independent samples t-test was used to compare the differences between the two groups. The results showed that the students who received a treatment by van Hiele’s instructional model demonstrated significantly better than those who received by formal instruction in No. (7), BEMS, Hlaing (t = 12.776, p < .001) and in No. (9), BEMS, Insein (t= 11.778, p < .001). The qualitative data also supported the findings from the experimentation. For this research study, students of the experimental groups were given a questionnaire. It consists of (15) items five-point Likert-scale and (3) open ended questions. The results showed that the students expressed their willingness to learn in van Hiele’s instructional model and they had positive attitudes towards van Hiele’s instructional model. Research findings proved that van Hiele’s instructional model has positive contribution to the geometry teaching at the middle school level.