Other important data points:
In every OECD country (including Mexico), students in socioeconomic advantages (are richer, live in better communities), obtain on average 39 more points in math, the equivalent to a year in school, than a student lacking those same advantages, which is why the study emphasizes policies that address inequality head on.
Preschool is essential. Those with a year or more of preschool managed 53 points more in math compared to those that didn't.
There is a gender gap. Boys on average scored better on math in 37 out of 65 countries and economies in the 2012 test and girls in five countries better in reading while increasing their advantage over boys in the other 11 countries. A gender gap exist, but the improvement of both boys and girls in all three categories suggest that it could be smaller or eliminated.
Shanghai, Hong Kong and Macao, got the highest marks in math, above the OECD avarage, followed by Singapore, Chinese Taipei (Taiwan), South Korea, Japan, Liechtenstein, Switzerland and the Netherlands.
Now, don't take the high performance of some Chinese cities as a representation of China as a whole, since there is some controversy around the fact that only the economically developed and advanced cities like Hong Kong, Macau and Shanghai are presented as China's entries into the PISA Test but not the vast majority of its rural and other provinces.
The U.S. especially takes issue with this. Even though it has nationally shown null improvement in all three categories, if Massachusetts, Connecticut and other highly developed cities were the only ones to submit themselves for rating, they too would show up in the top ranks among some Chinese cities.