If kids entered the classrooms one year earlier, it would send Danish school children directly to the top ten in the OECD's international PISA test of 15-year old students, the think-tank Kraka says.
In the most recent PISA rankings, Denmark came in at number 22 on the overall list of 65.
That result can be improved upon by not only focusing on what children learn in the classrooms, but also how much time they spend there, Kraka's analysis concluded.
"If we want to improve the children's skills, it's an option to put them in school earlier," Kraka economist Nicolai Kaarsen told Politiken newspaper. "Our analysis shows that it's not just quality that matters. How early kids start in school also impacts how much they have learned by the time they turn 15."
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Kaarsen added that in almost all countries that perform better in the test, kids start in school a year earlier than in Denmark. Danish children start school during the year in which they turn six years old.
Opposition open, S rejects idea
The Kraka analysis predicts that Danish school kids would jump from number 19 to eleven in natural sciences, from 18 to six in reading, and from 15th to sixth place in math if they were to start school a year earlier.
Opposition parties Dansk Folkeparti and Venstre (V) said they are ready to test the think-tank's theory on a larger scale.
"We are very, very interested in giving it a closer look," V's education spokesperson Peter Juel Jensen told Politiken. "But we also have to look at the consequences. This isn't only about providing great results, it's also important how the kids are doing and if they like being in school. That is still the biggest motivation."
READ MORE: Teacher training decisive for reading scores
But government party Socialdemokraterne (S) won't consider the idea. According to S education spokesperson Ane Halsboe-Jørgensen, there are better ways to improve students' skills.
"The public school reform takes care of exactly that problem by giving students more Danish and math classes in the later years. We also work with learning skills in the early years and have homework cafés at the schools," she told Politiken. "We have to be careful using PISA as our only guideline. There are other things that matter."
