In 2010, the book "Deutschland schafft sich ab" (Germany Abolishes Itself) was created by Thilo Sarrazin. This has made a lot of people very angry and has been widely regarded as a bad move. Sarrazin's core thesis on the topic of education can be roughly summarized as follows:
The German birth rate is low, with less than 1.4 children per woman. This is contrasted by a large number of migrants, especially from Muslim countries, who have higher birth rates.
Many migrants have educational deficits compared to the German population.
Even after several generations, these migrants do not catch up with German society. This is due to genetic and cultural inheritance as well as little pressure to integrate.
In the long run, Germany’s educational achievements will deteriorate due to this demographic change.
Sarrazin's critics argued that he was right about some things, but that he painted too bleak a picture and mixed truths with falsehoods. They pointed out, for example, that there had been progress in the area of education among Turks, a large Muslim immigrant group.
Against the background of the recently published PISA study, in which Germany performed miserably, it seems appropriate to re-examine Sarrazin's thesis. In particular, I will use the latest PISA study to answer the question of whether, and to what extent, migration aspects play a role in the continuous decline of German education.
Is there a decline in the cognitive abilities of youths?
The PISA study regularly tests 15-year-old students from a majority of OECD countries in the subjects of mathematics, reading, and science. In the following analysis, I will focus on the German PISA results in mathematics1 for the years 20092, 2018, and 2022.
First, let's look at how Germany has developed in recent years.
After the “PISA shock” in 2000, the development was initially positive. However, since 2012, performance has been declining again. A particularly sharp decline can be seen from 2018 to 2022. So yes, the youth’s cognitive abilities are in decline (again). But why? Is Sarrazin right with his thesis that demographic change is hurting our performance?
Why is there a decline in the cognitive abilities of youths?
Graphical analysis
The following graph shows net immigration to Germany over the past 20 years.
It is noticeable that we have had a strong net immigration since 2010. The Syrian refugees of 2015 in particular stand out. Does this have an impact on our PISA performance?
Let's look at the performance of students in the years 2009 and 2022 by mother's country of birth3 to get an impression of the impact4 of migration background on mathematical performance.
In 2009, it can first be stated that children of German mothers perform better than children of mothers from other countries of birth.5 Turks in particular stand out due to their poor performance and large number. They thus drag down the overall average. What does it look like in 2022? Is there any progress?
It is initially difficult to see any differences from the previous figure, except that the “Other” group has grown. Immigrants that feed this group are probably mostly Syrians, Romanians, Bulgarians, and Afghans as these are the biggest groups of immigrants in the last years. Refugees from Ukraine are not yet included in the data. Unfortunately, the PISA data does not allow for more precise conclusions about the composition of the “Other” group.
Let us now consider the difference in mean values between the groups.
It is noticeable that the values of all groups have deteriorated. In particular, the large decrease of the “Other” group is worrying because of its size. Turks are relatively stable at a low level.
Let us take a step back and consider the average math performance of natives, first-gen students, and second-gen students over time.
Several interesting observations can be made. Firstly, from 2003 to 2018, the performance of natives is remarkably stable with a tiny, non-significant, negative trend. This trend may also confounded by the increasing number of third-generation+ students that are counted as native students in this figure. Secondly, the rise in performance after the PISA shock can be solely attributed to the increased performance of second-generation students. Thirdly, since 2009 the performance of first-generation students is dropping rapidly. Fourthly, in 2022 all groups are deteriorating.
In the early 00’s first-generation students were more successful than second-generation students. This fact may be confusing on first sight, as it is widely known that second-generation students tend to outperform first-generation students of the same group. However, the composition of these groups is radically different. In the 90’s and early 00’s migration to Germany was dominated by “Aussiedlers”. These are ethnic Germans who had been living in eastern Europe and Asia. They migrated back to Germany after the fall of the Soviet Union. In the previous graphs, they would mostly be filed under “Former Soviets” or “Poland”. As we can see, their performance is only slightly worse than the performance of native Germans. What about the second-generation migrants in the early 00’s? They are to a large degree Turks, the lowest performing group. These two facts explain the surprising result of first-generation migrants outperforming second-generation migrants for a while. Over time, as first-gen Aussiedlers become second-gen Aussiedlers, it is not too surprising that the performance of second-gen students improves.
Taken together, the facts so far suggest that there wasn’t much improvement in the German school system to generate improved PISA performance. If it was, we should have seen improved performance for natives and first-gen students as well. If better integration was responsible, we likewise should have seen an improvement in first-gen students. Instead, the increase in performance was probably just the natural consequences of the shifts in migration patterns from less performant groups (Turks) to more performant groups (former Soviets & Poles).
Let us now refocus on the recent decline in performance. The question I would like to answer in the next section is to what proportion migration related issues are responsible for the decline in Germany's performance level from 2009 to 2022.
Mathematical Analysis
First, we need to define who we mean by “German” and “non-German”. I will try to capture the native population under “German” as closely as possible. Unfortunately, the PISA data does not allow for a clean distinction between the native population and third-generation+ migrants. Therefore, I define German as follows: a student is German if he or she and both parents were born in Germany and also speak German at home. Everyone else is non-German.
Between 2009 and 2022, the proportion of Germans as defined here decreased from 76% to 60%. At the same time, the decline in performance among Germans was 24.5 points (529 → 504.5),6 whereas among non-Germans it was 40.2 points (490.9 → 450.7). In particular, the performance of first-generation immigrants has deteriorated by 70.3 points (478.6 → 408.3). As a result of these effects, the overall average performance of Germany has deteriorated by 36.8 points (520 → 483.2).
Migration thus has both a performance effect and a composition effect. The performance effect is defined as the reduction in Germany's average performance that is explained by the fact that non-Germans had a greater decline in performance than Germans. The composition effect is defined as the reduction in the average performance in Germany explained by the fact that there are more non-Germans, who show lower levels of performance. Formally, I define the effects as follows:
The performance effect is the difference between the performance that would have occurred if non-Germans had declined only as much as Germans, and actual performance. The composition effect is the difference between the performance that would have occurred if the proportion of Germans in the population had not changed, and the actual performance. The migration effect adds both effects together.
This results in the following effects for the period 2009-2022.7
Compared to the total decline of 36.8 points, about 1/3 is thus related to migration! In plain language: if the proportion of non-Germans in the population had remained constant between 2009 and 2022 and the performance of non-Germans had changed in parallel with that of Germans, 1/3 of the decline in overall performance could have been avoided! Each year, Germany's mathematical performance diminishes by about one point due to the combined effects of composition and performance! For reference: 25 points roughly correspond to one year of schooling.
What about Covid?
Much of the decline from 2018 to 2022 is likely due to the Corona pandemic. It is, therefore, interesting for two reasons to examine the 2009 to 2018 period more closely. First, it could be that Covid affected different population groups differently. We want to avoid this effect. Second, Covid brings great uncertainty that is unlikely to recur. So it is interesting to estimate how important migration aspects are in normal times.
Repeating the analysis from before, we arrive at the following values for the period 2009-2018.
This contrasts with an overall average decline in performance of 11.9 during this period. The migration effect thus accounts for 84% of the total performance decline in the non-pandemic period (2009-2018)! In comparison, Germans lost only 1.8 points during this period. The relatively small difference between the migration effects between 2009-2018 and 2009-2022 indicates that the decline in performance between 2018-2022 is indeed largely due to the pandemic.
Interim Conclusion
The youth’s cognitive abilities are in decline and this seems to be largely explained by three factors: firstly, the consequences of the pandemic; secondly, the particularly poor performance of recent migrants; and thirdly, the increase in the proportion of the non-German population. If we do not change our migration and integration policy, we will slowly but surely become less performant, initially at a rate of about one point per year.
Advice to PISA: Please update the countries of origin. The time of the Cold War is over. This should be reflected in the data. Moreover, more information should be collected about the origin of the children in order to identify third-generation+ migrants.
Implications
Better integration of migrants is an obvious solution to the problem I have described. However, the question arises as to whether this is even possible or realistic. It is unlikely that our integration performance has deteriorated strongly in the last 10 years. It is much more likely that firstly, such a massive number of immigrants cannot be properly integrated at all, and secondly, that the cognitive ability of the average immigrant has deteriorated dramatically. After all, it is known that the school performance of immigrants depends much more strongly on where they come from than on where they go, indicating that migrants inherent abilities are more important than integration efforts of the host nation. Therefore, both a reduction in immigration numbers and a more selective immigration are needed.
One objection to stricter migration laws could be that even low-skilled people can make a contribution to society, for example by working in an area with a shortage of workers. This may be true. However, the average level of education is one of the most important factors for the prosperity and quality of life, especially for resource-poor countries. Just look at the ranking of the latest PISA results. Would you rather live in one of the above-average countries or one of the below-average countries?
Is restricting migration a sufficient solution? Women with German citizenship currently have 1.36 children per woman. In contrast, women without German citizenship have 1.88 children per woman. This alone means that we will continue to experience a composition effect. One might object that there are intergenerational improvements among migrants leading to a negative performance effect. However, these are only moderate and do not allow later generations to catch up to the native level. For example, in 2022, students who were themselves born in Germany, but whose parents were both born in Turkey, had a score of 422.3. As stated before, Germans had an average score of 504.5. It is unlikely that particularly large gains will be made between the second and third generations, assuming that both parents are not native, which is usually the case. After all, migrants of the 2nd generation have already been socialized in Germany and have mostly learned the German language. Where is the great advantage of the third+ generations compared to second generation supposed to come from?
Consequently, further measures have to be taken if we want to avert the decline in the level of cognitive abilities. For example, the repatriation of refugees to safe countries of origin, the deportation of foreigners obliged to leave the country and criminal foreigners with a tolerated status would be possible measures. Programs to support the voluntary return to home countries for selected groups are also conceivable.
Finally, an active family policy is also essential, with the goal of generating more offspring, especially among educated Germans (with or without migration background). This can be done by strengthening the principle of subsidiarity. Perhaps I will write a separate post about this at a later time.
A few final notes on pandemic prevention and management. In East Asian countries, there is hardly any visible effect of COVID-19 on PISA performance levels. We could learn pandemic coping strategies from them. One question is to what extent school closures can explain the different changes in performance. Widespread use of masks could also have had an effect. Furthermore, as part of pandemic prevention, pressure should be put on certain countries to close their “wet markets” as well as unsafe virus research laboratories.
Conclusion
The German youth’s cognitive abilities are in decline and this is mainly due to the pandemic and misguided migration policies. Stronger selection in immigration and emigration, an active family policy, and better pandemic control are possible solutions.
I choose the mathematics results as the basis for my analysis, as it is most related to the cognitive abilities of participants. Mathematics performance is also likely to be less susceptible to language deficits compared to reading comprehension. My aim is to examine whether migration has a significant impact on Germany's average cognitive abilities, not whether migrants are less proficient in the German language.
2009 is my chosen base year, as this is around the time Sarrazin developed his theses.
Using the father's country of birth yields almost identical results.
By impact, I mean indirect impacts as well. For example, if migrants of a certain group are poorer on average and it is actually poverty that causes the cognitive deficits, this would be included in the term “impact”.
Countries of origin were mostly taken from the PISA study. I have subsumed some places with few entries under “Other”. Students with unknown origin were excluded from the data.
I would like to point out once again that this number should be treated with caution. Since it is not possible to cleanly separate migrants of the 3rd+ generation from native Germans, and due to the imbalance in birth rates, an increasing proportion of “Germans” will have a migration background. This tends to underestimate the performance of native Germans. Thus, the estimated migration effects are also underestimated and should be seen as rather conservative.
Positive effects mean a decline in performance. The migration effect is smaller than the sum of the two effects, as there are negative interaction effects. If non-Germans had declined less strongly, it would not be quite so bad if there were more of them.