Expressen reveals that the Swedish Pisa results have been tampered with illegally. Sweden has excluded from the tests a large number of students who have poor Swedish skills.

The Pisa test measures the skills of 15-year-old schoolchildren from different countries. For a test to be comparable, it is governed by precise rules.

According to the rules, students who take the test will be drawn. If the lottery hits a student who has studied in the country for less than a year, he or she can be excluded from the test.

Expressen reveals that Swedish principals have excluded a large number of pupils who have been in Swedish schools for more than a year due to poor language skills. There are probably even Swedish-born students in this group. Two principals confessed the matter to the magazine.

According to Expressen's calculations, Sweden's result would probably have been considerably weaker if the country had strictly complied with the rules. Sweden was pleased with the improvement in the Pisa result in 2018, but it is likely that the country's result should have been weaker than in the previous test in 2015.

Sweden lagged behind Finland in all measured subjects in both 2015 and 2018.