After a ruling by the German Federal Constitutional Court in December 2017, universities in Germany will in future be prohibited from selecting applicants for a place of study solely on the basis of their grade in their higher education entrance qualification. Universities are therefore faced with the challenge of developing selection procedures that determine the suitability of applicants and which select the "best candidates" for entrance. This paper presents the theoretical foundations and empirical results of a selection procedure for applicants to a teaching degree program. In addition to cognitive abilities, that procedure also assesses prior knowledge and the extracurricular commitment, interest, motivation, and prior pedagogical experience of prospective students. The aptitude for study determined in this way in the selection procedure correlates positively with the later academic performance of the applicants.