Not only are they the best in the world when it comes to science, math and reading , a new international education assessment suggests they have the best social skills.

The findings on students' collaborative problem-solving skills were released Tuesday and are part of the Program of International Student Assessment (PISA) conducted by the Organization for Economic Cooperation and Development (OECD).

The survey, which assessed half a million 15-year olds, also found that girls have better social skills than boys and the United States ranks better on this measure than the country's academic standings would suggest.

What's more, the survey indicated, after school activities matter -- students who played video games scored lower in social skills than those who did not.

The report is the first international assessment of students' social skills, according to Andreas Schleicher, the OECD's director of education and skills, who says that the report addresses a growing demand in the workforce for individuals with strong social skills and an ability to work in groups.

"In today's schools, students typically learn individually, and at the end of the school year, we certify their individual achievements. But the more interdependent the world becomes, the more it needs great collaborators and orchestrators," he said.

US outperforms China

Broadly speaking, students who have stronger reading, science and mathematics skills also tend to be better at collaborative problem solving.

Singapore, long considered an education superpower, came top, matching its performance in PISA's individual academic rankings released in December last year. But it's not necessarily always a direct correlation.

Japan ranked second while four other East Asian economies scored above average: South Korea, Hong Kong, Macau and Taiwan. However, Chinese students did far less well in social skills, coming 26th, compared with 10th in individual academic performance.

"The results are really interesting, and for some countries they tell a very different story than what we see from individual academic skills. And it is more than culture: Japanese students do well in individual skills but they do even better in social skills," Schleicher said.

The United States was just outside the top 10 -- much better than its average performance in reading and science and below average math ranking.

Other countries where students performed above the average were Canada, Estonia, Finland, New Zealand, Australia and Germany, Denmark, UK, Netherlands, Sweden and Austria.

Despite the high value placed on social skills by employers, the report noted that these skills aren't usually explicitly taught in schools.

Yet, workplaces are beginning to place a premium on sociability, and the increase in the number of jobs requiring a high level of social skills has been paralleled with an increase in wages for such jobs, it added.

PISA assessed students in a number of ways. These included jigsaw tasks where each group member is given different information or skills; consensus building tasks, where groups must come to a decision after considering everybody's opinion and negotiation tasks, where not all group members share the same individual goals.

Girls outperform boys

In every country and economy that participated in the survey, girls scored far better than boys in collaborative problem solving.

These differences were most exaggerated in Australia, Finland, Latvia, New Zealand and Sweden, where girls score over 40 points higher than boys, on average.

Girls also reported more positive attitudes towards relationships, suggesting that they were more interested in other people's opinions, and wanted others to succeed. Boys, on the other hand, were more concerned with the instrumental benefits of teamwork, and the ways in which collaboration could work to their advantage, Schleicher said.

"It is all very well for boys to understand that teamwork can bring benefits, but in order to work effectively in a team and achieve something in a collaborative fashion, boys must be able to listen to others and take their viewpoints into account," he said.

After school activities matter

The report also found that students who played video games typically scored lower than students who didn't play them, even after accounting for social and economic factors.

However, students who used the internet, and communicated via chat rooms or social networks demonstrated higher collaborative problem solving.

Students in every country and economy seemed to have a generally positive attitude towards collaboration.

On average, 85% of students surveyed agreed with statements such as "I am a good listener," "I enjoy seeing my classmates be successful," "I take into account what others are interested in," "I enjoy considering different perspectives," and "I enjoy co-operating with peers".

All countries need to invest far more resources towards equipping their students for the jobs of the future, the report said.

"In world that places a growing premium on social skills, a lot more needs to be done to foster those skills across the school curriculum," said Schleicher.

"Strong academic skills will not automatically also lead to strong social skills."