The article proposed a method of use of probabilistic assessments of student performance. Between estimates of probabilities of receiving is «excellent», «Satisfactorily» and average progress of students the functional dependences are found. It is noted that the distribution of the probabilities derive a «well» is not informative for the detection and evaluation of factors affecting the academic performance of students. Therefore the hypothesis of existence of two psychologists – pedagogical characteristics of the student which correlate with decreasing and increasing probable functions is formulated. It is noted that the assessment of the likelihood of receiving «excellent» is not zero even for very weakly successful students that may be of interest to determine the career counseling of students. This is a technique removes problems of limit transition, and also allows to make the assumption that subclasses selected based on the probable analysis can have own structures of the factor space, describing students' motivation to learn. Methods of probabilistic analysis of student performance provides a more informative basis for psycho-educational research so explicitly reflects the trend towards obtaining excellent and satisfactory ratings. Therefore, the found dependences may be useful for predicting academic performance and help better meet the needs of researchers.