Prior to the year 2000, the Certificate of Sixth Year Studies (or CSYS) was the highest level of qualification available to pupils in the Scottish secondary education system.
Overseen by the Scottish Examination Board (SEB), it was taken by students in their sixth (and final) year of secondary education (ages 16-18) and was available for a range of different subjects. Examinations were administered by the SEB (and latterly by its successor, the Scottish Qualifications Authority, which replaced it in September 1997). Unlike the Standard and Higher Grade examinations, it was not a part of the Scottish Certificate of Education.
The CSYS followed on from Higher Grade examinations and was considered broadly equivalent to the English A-Level qualification. However, it never quite gained the same level of universal recognition as the Higher or A-Level. In particular, universities rarely used it when considering potential students.
Following plans for extensive reorganisation of the secondary education system in the late 1990s, the CSYS was phased out, starting in the 2000/01 examination year. By 2002/03, it had been completely replaced by its successor, the Advanced Higher.