The Hellenic educational system is governed by laws and administrative acts. The Ministry of National Education and Religious Affairs, which implements the national policy for education, has the overall responsibility. Education in Greece is compulsory for all children 6-15 years old. Formal education is characterized by the fixed length of study, the possibility of repetition, and the award of a formal school-leaving certificate, which is the official recognition. A diploma (school-leaving certificate, degree, etc.) is compulsory for students at each educational level in order to continue to the next.