For policymakers searching for reasons for the dominance of East Asian countries in the latest global education rankings, one potential explanation is how well they succeed with students at the bottom of the economic pile.
The Programme for International Student Assessment (Pisa) data published last week suggests a strong correlation between overall high performance and the percentage of disadvantaged 15-year-olds managing to achieve educational standards that are among the best in the world.
The study describes the phenomenon as "resilience", which in practice means poor children beating the economic odds to do well.
"Across most countries and economies, socio-economically disadvantaged students not only score lower in mathematics (the main focus of the latest assessment), they also reported lower levels of engagement, drive, motivation and self-beliefs," the study says.
Resilience in education is often seen as being to do with self-esteem and well-being, but the definition used by the Organisation for Economic Cooperation and Development (OECD), which runs Pisa, is narrower.
In the study's terms, "resilient" students are in the "bottom quarter of the socio-economic scale" in their country, but have Pisa test scores that rival the top 25 per cent of students across all participating countries. The Pisa report says that nearly 1 million students across the industrialised OECD countries manage that feat, although there is significant variation between countries.
On average, 6 per cent of a country's entire student population manages to transcend their economic background to do well in Pisa. But that varies from a low of just 0.5 per cent of all students in Peru and Qatar, all the way up to 19.2 per cent in Shanghai, China, which topped the rankings in maths, science and reading.
In fact, of the eight territories that finished top in the maths table, seven were also among the top eight for resilience. The one star performer outside this elite group was Vietnam, but with a debut Pisa ranking of 17th, it is hardly a slouch, and the fact that it has the fourth highest proportion of students who are resilient - 16.8 per cent - could have a lot to do with that success.
Andreas Schleicher, the OECD official who runs Pisa, has argued that the culture of East Asian countries cannot be used to explain the phenomenon. "Look at Vietnam and Thailand," he said. "(They are) countries in a very similar context: Vietnam rapidly rising - one of the real successful education systems - and Thailand, staggering along at very low levels of performance.
"You can live in a very similar cultural context and come out with very different results."
But experts have questioned whether education policy alone would be enough to replicate that kind of achievement in other countries seeking to boost the performance of poor students.
"What the results demonstrate is the impact of economic policies that actually herald the prospect of individual success," said John Bangs, chair of the OECD's Trade Union Advisory Committee's education working group. "That is why (students) are all working like lunatics in Singapore and Shanghai."
"I think it is to do with a national sense of why education is important," he added. "If you take white working-class kids in the UK, they are at the bottom of the pile when it comes to achievement and the reason for that is there is a sense that pride has been knocked out of them.
"Policy has to focus on that. There is absolutely no aspiration among people who know that their parents are unemployed, and they will be probably be unemployed, and so will their children.
"It is an overall policy thing. I don't think it is just to do with education. The elephant in the room is the cultural issue."
Gabriel Sahlgren, research director at the Centre for Market Reform of Education in London, was sceptical about the usefulness of the finding, because it did not explain why children from poor backgrounds were doing well.
"Is it a cultural issue here? Is it the school?" he said. "We have no idea. What does this tell us about their policies?"