Several attempts have been made to measure and categorize beliefs and practices of mathematics teachers [Swan, M. 2006. "Designing and Using Research Instruments to Describe the Beliefs and Practices of Mathematics Teachers." "Research in Education" 75 (1): 58-70]. One of the reasons for measuring both beliefs and practices is to characterize teachers in terms of the relationship between their beliefs and practices. However, the practice-instruments and the beliefs-instruments discussed in the literature are predominately based on differing constructs. Consequently, it is challenging to compare the relationship between beliefs and practices solely based on these instruments. As such, we argue that practice- and beliefs-instruments based on the same construct would be desirable when both beliefs and practices are at stake. This paper presents two Rasch-calibrated instruments that measure the level of teacher-centredness with respect to student teachers' practices and beliefs about teaching mathematics. From a sample of 160 student teachers, 15 items have been established as being beneficial for measurement, both when the items are translated as practice items and when translated as beliefs items. By studying the invariance between both translations, we conclude that measures from both instruments can be directly compared.