The educational variable (PGISCED97) classifies all correspondents' educational degrees according to the “International Standard Classification of Education (ISCED)” of 1997 in order to make degrees internationally comparable. The variable is generated retrospectively from 1984 onwards taking into account degrees and diplomas attained in both general schooling and in vocational/university education and indicates the highest degree obtained. E.g., persons who did not indicate secondary school degrees/diplomas but a university degree are placed in the highest ISCED category. Please note that, due to a lack of more detailed information on tertiary degrees in earlier waves -- in particular on PhD -- we include all tertiary degrees in ISCED category 6. Thus, the ISCED variable provided here is not comparable one-to-one with the ISCED levels as defined by the OECD, since we have included the original ISCED level 5A in our ISCED category 6. OECD (1999): Classifying Educational Programmes: Manual for ISCED-97 Implementation in OECD Countries, Paris.