As a consequence of the ten-year school, known as the polytechnical high school (Polytechnische Oberschule, POS) and planned as the general compulsory school from 1959 to replace the previous eight-year compulsory school, the upper secondary school was henceforth referred to as the extended secondary school (Erweiterte Oberschule, EOS). It replaced the previous secondary school that led to secondary-school graduation (Abitur) after four years. The requirement of the Law on the Socialist Development of the School System of December 2, 1959, to combine school and vocational training, resulted in the stipulation that EOS vocational training had to be completed at the same time as a general university entrance qualification was to be obtained. However, the shortening of the EOS to two school years following the ten-year compulsory school, which had become apparent since 1965, no longer allowed for simultaneous vocational training. The goal of unified school policy, which was set out in the Law on the Unified Socialist Education System of February 25, 1965, of allowing pupils to move on to an EOS of just two years after completing the compulsory POS, was a source of considerable conflict. In preparation for the reduction in the length of the four-year EOS, so-called transition classes were introduced at the EOS in 1968/69, for which the POS curricula applied.

In addition, the vocational training with Abitur (Berufsausbildung mit Abitur, BmA) form of education, fraught with organisational problems, economically unproductive and with no effect on pupils' studies, was phased out from 1967. It was replaced by 'scientific-practical work', which took the form of project work in suitable companies for small groups of pupils four hours per week in grade 11 and in the first half of grade 12. In addition to the EOS (1.6 percent of all schools in 1990), the university entrance qualification could also be acquired in special schools (0.6 percent), children's and youth sports schools (0.5 percent) (cf. Uhlig & Wiegmann, 1994) and in adult education institutions.

The BmA was also retained until the end of the GDR. This route was used by those pupils who were interested in studying after completing the 10th grade with good grades, but who had not applied for the EOS after the 8th or later during the 10th grade for various reasons, or by those whose application had previously been rejected. They were thus able to obtain both the general university entrance qualification and a skilled worker's certificate in a special Abitur grade at a state-run vocational school in a three-year course.

From 1982/83, the Ministry of Education (Ministerium für Volksbildung) consistently implemented the provisions of the current education laws. The admission criteria, which were set according to economic, social and political indicators, provided further sources of social conflict, and generally only allowed one or two pupils in a class to move on to the EOS. There was no legal entitlement to do so. In addition to academic performance, the decisive factors for admission by commissions headed by the school council responsible were social commitments of the pupils. Minimum political requirements for the parents and the political loyalty of the applicants were assumed. Social background (support for so-called workers' and farmers' children, Arbeiter- und Bauernkinder) and other measures to create a so-called socialist intelligentsia played a significant role, especially in the first two decades after 1945. The graduation rate from all educational institutions leading to university entrance qualifications rose from around 3 percent of an age cohort in the first post-war years to an average of 14 percent since the 1970s. EOS graduates achieved an average share of 8-9 percent. Around 98 percent of school graduates went on to study at university level, with around 80 percent of the first-year students successfully completing their studies (cf. Geißler, 2023, pp. 1143-1220).