The article contains a study of the principles of student's educational trajectory formation by using modern technologies in data analysis. There is a mandatory requirement to have the selective component (optional to a student) among the curriculum educational components. This rule is legislated in the laws «On Education» and «On Higher Education» of Ukraine as well as in the normative documents on accreditation of educational programs, defined by the Standards and recommendations on quality assurance in the European Space of Higher Education (ESG) and the National Agency for Quality Assurance of Higher Education. However, adherence to the principles of the individual educational trajectory formation is mostly formal and is reduced to offering students a non-coherent list of courses. On the one hand, this leads to the disorientation of a student, who cannot see the systemic perspective of his future profession in the initial list of study courses, and therefore cannot consciously choose the optimal set of optional courses. On the other hand, the unknown choice of courses by students leads to situational management of the educational process at the HEI. A large number of courses create significant difficulties in managing the selection process. To analyse the process of individual educational trajectory formation, the authors propose to use methods of data association and, in particular, the apriori algorithm for the formation of associative rules. The procedure of popular sets of elective courses formation, the configuration of associative rules of educational courses choice is studied. The characteristics of these rules quality are calculated. The example of the procedure implementation in analytical platform Deductor Studio is considered.