The authors suggest a new concept of evaluation of general school students’ achievements. The concept is based on a three level model of the individual progress. In the article, they provide a detailed structured defi nition of the individual progress, and provide arguments for the methodological and technological possibility of its measurement using an original method ‘Delta’. The authors present the routines and results of test material validation. They discuss prospects of usage of grades obtained by the ‘Delta’ system in the interest of various participants of the education process, namely, teachers, students, and their parents.