The problems of developing diagnostic indices, which could differentiate categories of deviant behavior in children and adolescents in the context of psychological, medical and educational committees’ (PMEC) activities are considered. The main goal of PMEC is timely detection of children with peculiarities in their physical and / or mental development and / or behavior deviation, their complex psychological, medical and educational examination and, on the basis of its results, development of recommendations for the corresponding assistance and organization of their education. This group of minors includes children and adolescents not only with limited health conditions, but also with different kinds of deviant behavior and in conflict with the law. In the article, the analysis of pupils’ personal files from special closed educational institutions for minors in conflict with the law is presented. The methodical instrument for the structured assessment of a child’s social situation of development in the work of a PMEC approved in the framework of the project “Development of scientific-methodical provisions for the PMEC work concerning examination and producing recommendations for pupils with deviant behavior and in conflict with the law” is described and used.