The study set to investigate the Finnish matriculation examination with a focus on the subject of social studies. The goal was to examine how well the subject-specific exams of the examination measure students' attainment in the courses of the respective subjects across upper secondary studies. The data was drawn from a longitudinal study of 6,172 Southern-Finland upper secondary students in 62 schools who passed their matriculation examination in spring 2017. Data on students' upper secondary school course choices and attainment was received from the schools and matriculation examination results from the Finnish Matriculation Examination Board. Key finding of the study is the unanimity between the two assessments: students' grades in the subject-specific exams of the matriculation examination correlated strongly with their respective grades across the courses during their three years of upper secondary studies. The findings give strong support for the matriculation examination as a curriculum-based exit exam and for its use in student admission to higher education.