The factor analysis of pupils’ marks at the secondary school of economics, marks in the main subjects at the Elementary Nine-Year School and some other data have confirmed the existence of a strong common factor underlying the pupils’ marks in an overwhelming majority of subjects. This factor has been interpreted as school efficiency, i. e. a relatively stable complex of personality pre-requisites of the pupil for the fulfilment of classroom requirements. The factor analysis has also confirmed the pattern of specific school efficiency for the elementary school and the secondary school of economics. It was possible for most of the 8 rotated factors to be satisfactorily interpreted by means of common demands of the subject groups on the pupil’s specific personality pre-requisites. The following factors have been ascertained: economico-social-science, verbally linguistic, mathematical and practically economic. Confirmation of the stability of the factors ascertained would allow a sensible interpretation of differences in a pupil’s marks — his school results — as individual differences in the classroom efficiency structure.