While Sweden's own education authorities have admitted that foreign-born pupils tend to average lower results, Sweden leads the recent international student assessment programme in terms of the percent of students whose results were disregarded, ostensibly due to the newcomers' poor command of the country's native language.

According to the newly-published results of the Programme for International Student Assessment (PISA), which tests 15-year-olds' scholastic success in reading, mathematics and science in 79 countries around the globe, Sweden has upped its performance from “well below average” to “above average”.

While the Swedish National Agency for Education's Director General Peter Fredriksson interpreted the data from PISA 2018 as a confirmation that “students, teachers and principals are doing a good job”, a closer look at the survey's data indicates that Sweden actually leads the entire survey in terms of the number of students whose exam results were disregarded due to poor knowledge of the native tongue, in this case Swedish, which has sparked accusations of data tampering.

The test results of wholly 11.1 percent of Sweden's 15-year-old were removed from the survey, up from 5.7 in 2016 and the highest of all the 79 participant countries who have an average percentage of exclusions of 4.0 percent. Admittedly, poor language skills due to immigration are the main reason for it.

“There is reason to believe that the increased rate of exclusion between 2015 and 2018 is mainly due to an increased proportion of students with limited command of the Swedish language. This is due to the migration flows that caused the great refugee crisis in 2015 and which is visible in the statistics of new arrivals in Swedish schools”, the Swedish National Agency for Education wrote in its report.

The report authors noted that Sweden stressed that foreign-background pupils, whose share has increased due to high immigration, tend to perform worse than students born in Sweden.

“Since foreign-born pupils with a foreign background tend to average lower results, an increased proportion will have a negative impact on the national average,” the report said.

Without the demographic change, the positive education trend could have been much more pronounced, national broadcaster SVT reported.

The idea that Sweden may have been doctoring its records to make them look better sparked outrage.

“The former alliance parties love to take the honour for Sweden moving up a little in the PISA survey. Do you also take credit for the fact that 11% of Sweden's 15-year-olds do not master the Swedish language? The National Agency for Education says it depends on the large immigration”, journalist Mira Aksoy tweeted.

De tidigare allianspartierna älskar att ta åt sig äran för att Sverige går lite uppåt i PISA-mätningen.



Tar ni även åt er äran för att 11% av Sveriges 15-åringar inte behärskar svenska språket? Skolverket säger att det beror på den stora invandringen.https://t.co/KUERXbJgRq — Mira Aksoy 🎄 (@miraaksoys) 4 декабря 2019 г.

​“According to PISA's own rules, a maximum of 5% of the students may be excluded from the survey. How Sweden has managed to exempt 11% should be a matter for journalists to investigate,” advocate and Moderate Party politician Henrik Sundström tweeted.

Enligt PISA:s regler får max 5% av eleverna undantas från mätningen. Hur Sverige har lyckats få undanta 11% borde vara stoff för journalistik.https://t.co/YY0u9bAAw7 pic.twitter.com/glXcIzlerd — Henrik Sundström (@HenrikSundstrom) 4 декабря 2019 г.

​“The government is drumming is chest, as the PISA survey shows that Swedish students are getting better. But over 11% of the students were not even allowed to participate, as they haven't mastered the Swedish language. There we have the explanation for the 'improvement',” blogger Projekt Morpheus tweeted.

Regeringen slår sig för bröstet efter att Pisa-undersökningen visat att svenska elever blir allt bättre.



Men över elva procent av eleverna fick inte ens delta – då de inte behärskar det svenska språket.



Där har vi förklaringen till "förbättringen".https://t.co/7CFqNRQZkr — Projekt Morpheus (@ProjektMorpheus) 3 декабря 2019 г.

​Tweet: “Fantastic employment figures. How did you manage to achieve then? Oh, we merely removed the 11 percent that stand farthest from the labour market.”

​Between PISA 2009 and 2018, the proportion of students with a foreign background increased from 12 to 20 percent, and the OECD itself estimated that Sweden's improvement would have been even greater if the pupils' demographic profile had not changed, according to the newspaper Dagens Samhälle.