Revisiting the control group: problem-based learning's impact on the understanding of place value

The use of a control group is an effective tool which afforded this researcher a gauge as to the effectiveness of his change in pedagogy. However, the ethical considerations regarding the control group’s continued lack of understanding could not go unattended. This study revisits that control group. In the original investigation, both a control group and an experimental group were used to determine the effect a problem-based learning (PBL) pedagogy versus the traditional teacher-centred instructional approach in a university course will have upon pre-service teacher’s understanding of place value (PV). At the end of the study, the results suggest that the majority of the control group possessed a prestructural or unistructural understanding of place value systems, while the experimental group was found to be mainly thinking at a unistructural and multistructural level. Two years later, the control group was re-taught using the PBL method after being pre-tested for incidental learning. The pre-test results indicated they were found to still be mainly thinking at a pre or unistructural understanding. However, after being treated to the PBL instruction, the control group participants were found to be thinking at a unistructural, multistructural and relational level. Therefore, it is suggested from this study that a PBL approach does provide deeper understanding in pre-service educators’ understanding of place value