Abstract

• The main purpose of this study is to investigate the effectiveness of the cooperative mastery learning model in students’ achievement in middle school science teaching. This study was conducted by quasi-experimental design. As the instruments for this study, pretest and posttest were used. By using a random sampling method, four high schools from Mandalay and Sagaing Regions were selected. Cooperative mastery learning model was implemented on experimental groups. The control groups were exposed to formal instruction. ANCOVA results showed that there was a significant difference in the overall science achievement between middle school students who receive instruction with cooperative mastery learning model and those who do not receive it. Therefore, the findings of this study proved that students who receive instruction with cooperative mastery learning model were higher than those of students who do not receive it. In addition, it can be suggested that cooperative mastery learning model should be used in science teaching and learning.