Estonia holds a strong seventh position in OECD's biggest ever global school rankings based on maths and sciences skills at age 15.
Although the full report will only be formally presented at the United Nations World Education Forum next week, BBC has published the league table in advance. The rankings, based on test scores of 76 countries, offer a wider global map of education quality than OECD's Pisa tests, and so aim to show developing economies how they can grow if they raise their education standards.
"The idea is to give more countries, rich and poor, access to comparing themselves against the world's education leaders, to discover their relative strengths and weaknesses, and to see what the long-term economic gains from improved quality in schooling could be for them," OECD's education director, Andreas Schleicher, told BBC.
Asian countries occupy the top five places in the table, with Singapore once again topping the scales. Finland and Estonia take neighborly sixth and seventh places.
The UK is placed 20th, the US 28th, and Sweden has dropped to 35th, one step behind Russia (34th). Latvia and Lithuania are ranked 24th and 31st respectively.
Ghana comes in last at 76th, behind South Africa, Honduras and Morocco.
Rankings based on maths and science, at age 15:
2. Hong Kong
3. South Korea
Visit BBC for the overall rankings and interactive maps.