At that time in China, higher education was still recovering from the Cultural Revolution; school transcripts and recommendation letters were difficult to evaluate.
[1] According to US physicist Sam Treiman, early applicants to the program included many older students, whose education had been interrupted by the Cultural Revolution.
[1] Among them, about 100 Chinese students selected by their CUSPEA exam scores entered the subsequent application process to go to their PhD studies in the US.
CUSPEA was so successful that other similar exams soon were created, such as CUSBEA for biochemistry and "Shiing-Shen Chern Project" (陈省身项目) for mathematics.
Mini-CUSPEA applicants sit written exams and attend interviews, similar in style to the old CUSPEA admission tests.