The article describes the findings of the historic-theoretical study of research methods utilized by preschool teachers in terms of analysis of understandings about their specificity in the national psychological and pedagogical science. The aim of this study is to uncover the strategies for studying children through observations and comparison forms of the documentations of results conducted by the preschool teachers. The analysis was performed beginning from the preschool teacher’s diary designated by research team under the guidance of
O. Dyachenko to the maps of development for the modern curriculums of preschool education (“Beginnings”, “From the Birth to School”, “World of Explorations” etc.). The main method of the study is a problem analyses, that allowed defining the goals and tasks of the use of the diaries and development maps as tools of documentation and analyses of results through observation; rules and choice of developmental milestones in children for the diaries and maps; methods of filling them up, analyzing and interpreting data. Directions for the improvement of design, implementation and analysis of the diaries and development maps children are identified. The conditions for effective interaction between preschool teacher, psychologist and other specialists through implementing of strategies for exploration of children are discussed. The objectives for the development of professional competences in preschool teachers in the area of pedagogical diagnostic are given.