With the increase in the number of university students, the number of those who do not finish successfully the tertiary education is also increasing. The article uses a specific data source and analyses only a part of the group of unsuccessful students who re-enroll. This is a specific group of students - they did not finish the tertiary study in the past, but after some time they returned to education. The aim of the paper is to find significant factors that influence the decision whether the student changes the studied school or field of study. Factors will be searched using decision trees and binary logistic regression. Both methods were significant for gender and the fact that a student is studying his preferred university. Logistic regression adds to the student's health disadvantage. The data were obtained from the EUROSTUDENT survey, which was held in the Czech Republic in 2016 under the auspices of the Ministry of Education, Youth and Sports. The results can be used to identify a risky candidate or student at the beginning of tertiary education.