| While continuity between lower secondary schools and upper secondary schools is not guaranteed, nor compulsory, the proportion of students going on to upper secondary schools is 97%. Public lower secondary schools are established by municipalities as components of the compulsory educational system while public upper secondary schools are established mainly by prefectures as non-compulsory education school. Achievement tests are required to enter upper secondary schools. The negative effects of these tests on education and instruction at lower secondary schools has been criticized despite the fact that virtually all students proceed on to secondary schools. Since lower secondary schools and upper secondary schools are integrated in many private schools, a shift in studentsf and their parentsf preferences from public to private secondary schools has been occurring. Given the above situation, comprehensive secondary schools have been defined as the tenth type of schools in Article 1 of the School Education Law, under the revision of the Law undertaken in 1998. Comprehensive secondary schools are six-year-schools that are divided into a lower division (three years) and an upper division (three years). While it is still possible to transfer to lower secondary schools and upper secondary schools in mid-stream, the key feature of comprehensive secondary schools is their six-year integrated curriculum.