I am not so keen on the subject as I used to be. It was something I looked into after seeing Shanghai outscored everybody in the PISA. So the following information is a bit dated.
Here are some of the provinces and municipalities tested and their respective ranking on the 2012 Gaokao: Tianjin (15,12), Shanghai (16, 10), Beijing (26,24), Jiangsu(21,11), Zhejiang(9,5), Jilin(22,21), Hubei(8,4), Hebei(4,3), Hainan(12,23), Sichuan(25,17), Yunnan(24,27), Ningxia(29, 29).
(There are 31 jurisdictions in total, and the ranking is based on the grades required to get into a first tier university within the province. The first number is for arts, and the second number is for STEM).
If “geographical distribution” is not practiced, Beijing and Tsinghua will be overrun by students from places like Hebei and Zhejiang. Shanghai too would not be immune. There would be riots on the streets.
Of greater concern to me is the huge gap in performance among jurisdictions. Based on the results of 2012, a Cantonese needs to score 78.53% to get in a first tier college in the arts faculty in top scoring Guangdong, while a Tibetan needs only 42.67% to do the same in Tibet. I think this is where a lot of the discontent is coming from: those minorities simply can not compete.
The Chinese leadership has a serious problem on their hands. How do you make unequals appear equal?