The "Sad Smiley": Test Performance of German Students over Time

To map the performance of German students over time, I collected all tests that tested representative samples of German students in mathematics, science, or German in a metric that is comparable over time. These are a total of 43 national test observations in eleven subject-specific tests from five testing cycles: PISA, TIMSS, PIRLS, IQB Primary, and IQB Secondary. After standardizing test performance and estimating the best squared fit line, a clear picture emerges, that of a "sad smiley": After the PISA shock, average performance increased by about 23 points (percent of a standard deviation) from 2000 to 2010-11. As a rule of thumb, this increase roughly corresponds to 70-90% of what students generally learn on average in a full school year. From 2010-11 to 2019, achievement decreased by about 14 points, or about 60% of the previous increase. The decline is evident on all available tests. The period of Corona-related school closures is not yet covered by the tests. The little-noticed downward trend should worry us because these basic skills are the foundation of children's future life chances and of our future prosperity.