Because there often are relatively small differences between countries, Exhibits 1.3 and 1.4 show whether the differences in average achievement among the countries are statistically significant.
At the fourth grade, Singapore and Korea were the top performing countries, with similar achievement and higher achievement than all of the other countries. The next highest performing countries were Japan and the Russian Federation, which had higher achievement than all countries except the two with the highest achievement, followed by Hong Kong SAR, Chinese Taipei, Finland, and Kazakhstan. Poland, the United States, Slovenia, Hungary, and Sweden also performed very well.
At the eighth grade, Singapore was the top performing country, followed by Japan and Chinese Taipei. The next highest performing countries were Korea and Slovenia, followed by Hong Kong SAR and the Russian Federation. England, Kazakhstan, Ireland, and the United States also performed very well.
