Dec 04

Unstatistik of December

"PISA results are not fully comparable internationally"

Unstatistik vom 02.12.2019

The Unstatistik of November is the expected poorly differentiated coverage of the PISA study. This is therefore a preventive Unstatistik, since the study only at 3. December is presented to the public. The goal is this time, to make the PISA report in advance better, instead of writing about it in retrospect. Even before the official publication of the OECD international student assessment study („Programme for International SMagnitude Assessment“) In early December provides the latest edition of the study for some noise in the German press. For example, reported the Frankfurter Allgemeine Zeitung am 28. November of past in a commentary of the education researcher Rainer Bölling entitled "slate as the leaning tower" of various problems PISA studies.

The aim of the study is to measure and compare school performance in reading, Mathematics and natural sciences. These figures are based on a sample. In contrast, nothing would be wrong with, this would be levied in all countries equally to the same standards of statistics. But that does not happen. In some Asian countries about, occupying top rankings in PISA, take only about 80 percent of students in randomly selected schools to the test tasks part, in Germany more than 95 percent. Which students fall through the cracks? There is certainly evidence, that in some countries, especially poorer students on PISA exam are sick or skip school. Thus apples are then but compared with pears.

The growing proportion of migrants at students in Germany is an important cause for the German mediocre by international standards cutting schools. The counter-argument the example of Canada is often listed, where there is also a high proportion of migrants, without this would do the school results demolition. But in Canada show children with a migrant background as a result of a selective immigration policy better average academic performance than native, they draw the average tends to be upwards. worse in Germany cut children from immigrant backgrounds on average in the school from the local, in particular, partly because they must first of all learn the German language. Push the average therefore tends to bottom.

regarded differently from mere rank comparisons results

It is hoped, that this time takes place compared to the past more sophisticated reporting and public discussion of the results of the PISA study. Thus, the authors of the studies have reported in the past, so-called confidence intervals, consider the article which results after sampling uncertainty in the estimation results. The differences between countries fall out sometimes so low, that many of these differences are not statistically significant. Also, in these reports in detail on the differences between children pointed with and without migration background. Both - both the uncertainty of the results and the differences between children with and without an immigrant background - was largely ignored in the public debate about PISA.

Therefore our request, not only to view the status of Germany in an international comparison problematic in the discussion of the results of the PISA study. Rather, you should focus on solving the own problems in the education system more. Here, the PISA study may well provide insights to relative deficiencies in some areas.


contact persons:

Prof. Dr. Thomas K. Bauer, Tel.:(0201) 8149-264
Sabine Weiler (Press Office RWI), Tel.: (0201) 8149-213

With the "Unstatistik of the month" of the Berlin psychologist Gerd Gigerenzer question, Dortmund statistician Walter Krämer and RWI Vice President Thomas K. Bauer each month both recently published figures and their interpretations. All "Unstatistiken" can be found on the Internet at