There are no cars in the car park at Hiidenkivi Comprehensive School; most pupils walk or cycle to school. Inside, they sit at tables of four in groups of mixed abilities. They have a say in what they learn and where: many work slouched against a wall in the corridor. Tests are rare. Lunch is free. The youngest pupils go home by noon with little or no homework.

Tens of thousands of visiting wonks have taken similar notes since 2000, when Finland came at or near the top for reading, maths and science in the Programme for International Student Assessment (PISA), an influential triennial test of 15-year-olds in 60 or so countries. Teenagers consistently score higher only in Japan, Singapore, South Korea and the richest parts of China. But unlike these places, Finland is said to have cracked schooling without working its pupils into the ground.

Inside the country, however, educators are worried. PISA scores fell in 2009 and 2012 (the next results will be published in December). Data suggest the slide began around the turn of the century. Children of immigrants tend to score worse, but native Finns’ scores have dipped, too. The problem is worst among girls from non-Finnish-speaking households and native boys: one in eight 15-year-old boys cannot read at the level necessary to keep studying.

A separate problem is that when Finnish children are in school, they are surprisingly glum. About half of 14-15-year-olds feel their teachers don’t care about their lives. Finnish pupils are more likely than the average OECD student to say that their classroom environment is bad for learning. Tuomas Kurtilla, the country’s ombudsman for children, says 20-25 percent of Finnish girls aged 14 and 15 receive school counselling.

Pasi Sahlberg, a former education ministry official, frets that Finnish education is repeating Nokia’s error: failing to innovate when on top. Literacy has traditionally been prized, says Sirkku Kupiainen of the University of Helsinki; until about 50 years ago the Lutheran church often would not marry Finns unless they could read. But between 2000-2009, the share of 15-year-olds reading more than 30 minutes per day fell from a half to a third. Teachers bemoan the siren song of the smartphone.

Finland is hardly alone in facing shifts in youth culture, notes Tim Oates of Cambridge Assessment, a testing company. Some countries, like England, have responded by tightening discipline. But Finland is taking a sensitive and “pupil-led” approach. In August, its 313 municipalities will roll out their versions of a new national curriculum meant to restore the “joy and meaningfulness of learning”.

Sceptics have two main concerns. The first is inequality. Finland’s gap between rich and poor pupils is smaller than in most OECD countries, but it has widened since 2000. Kurttila says well-off parents are renting flats near good (government) schools and entering pupils for competitive music classes to game the system. Critics of “phenomenon-based learning” say it will make things worse by reducing the time poorer pupils spend on core subjects.

Opponents also think the new curriculum undermines what they say led to Finland’s previous success: an idiosyncratic mix of culture, history and traditional education. Gabriel Heller Sahlgren of the Centre for the Study of Market Reform of Education, a think-tank, says the key question is what led to the surge in Finnish performance between 1965-2000, not what is happening in schools today.

Some of Finland’s strengths are hard to copy. Teachers have exceptionally high social status: only doctors are more sought-after as partners. Finland industrialised later than other Nordic countries and launched mass education only in the 1960s. Ms Kupiainen says this meant the parents of the “PISA generation” were upwardly mobile, and passed on a belief in the power of education. Younger parents, she says, worry that their children have not inherited their diligence.

But both defenders and opponents of the new curriculum agree that children’s will to succeed in school has diminished. “Ten years ago, education was highly valued among all Finns,” says Ilppo Kivivuori, deputy head teacher at Hiidenkivi. “Now that is less clear.” So is whether the reforms can turn things around.