In Germany students gain access to universities by passing the high school exit examination (Abitur/HSEE). By using probabilistic scaling methods, this study examines whether the HSEE as a form of high-stakes testing provides valid information for measuring competencies. For this approach a cohort of students simultaneously took their high school exit examinations in mathematics and the TIMSS/III-test (Mullis et al., 1998). Both instruments entail information about students' mathematical competencies. The presented study establishes the comparability of the tests and test results and consequences for each type of test.