German Federal Education Minister Karin Prien has reignited debate over how to raise classroom standards by suggesting that the share of pupils with an immigrant background in any given class could be limited to roughly 30-40%. Prien told Welt-TV the measure was one of several options under consideration as the government looks for ways to stem a decline in reading, mathematics and science scores recorded in international PISA tests. Immigrant children or those born to immigrant parents now make up almost a third of Germany’s school population, and more than half in major cities such as Berlin and Hamburg. Studies cited by Prien’s ministry indicate that about one in five children start primary school with insufficient German to follow lessons, a factor some education researchers say slows learning for entire classes. Reaction to the proposal has been mixed. Andreas Schleicher, creator of the OECD’s PISA studies, said international comparisons support a more even distribution of migrant pupils. By contrast, Social Democratic Party education spokeswoman Jasmina Hostert and federal integration commissioner Natalie Pawlik called the idea discriminatory and unworkable, noting that education policy is largely determined by Germany’s 16 states. Prien acknowledged the practical challenges and said no decision has been taken.