Berlin (dpa) - Almost two decades after the big "Pisa shock" and the subsequent upward trend shows the performance curve of German students back down. In the international Pisa comparative test, Germans scored lower in all three areas of reading, mathematics and science than three years ago. Even then, the values ​​had deteriorated in two areas. Overall, Germany remains above the OECD average. Mediocrity could not be the claim, said Federal Education Minister Anja Karliczek.