[Hygienic Assesment of Educational Texts: Methodical Approaches and Evaluation of Difficulties for Children of Secondary Textbooks].

BACKGROUND The understandability and readability of the text are significant indicators of evaluation of textbooks. OBJECTIVE The aim of the study - rationale of improving the readability and understandability of textbooks. METHODS 60 modern textbooks for 5-11th classes on History, Physics, Biology and 23 textbooks of 1960-1980's edition. Flesch index was used to assess the readability, Fogh index - to evaluate understandability. RESULTS The readability and understandability of texts in textbooks of 1960-1980's and modern editions have no differences and show the same complexity of old and modern textbooks for students. The indicator of understandability of textbooks for primary classes corresponds to age norm and is 4.4±0.2 points. The indicator of readability for these books is less age norm and is 53.8±2.9 points, which increases the physiological cost of educational activities of children of primary school age. Children's readability and understandability of school textbooks are a significant factor of intensity of training activities and can be objectively assessed by Flesch and Fogh indices, that it is appropriate for an objective hygienic assessment of the tension of the educational activities for children. CONCLUSION The main direction of optimization of the tension of educational activity is to reduce the intellectual and emotional loads in children by increasing the easiness of reading textbooks due to their compliance with the age peculiarities of students.