People's Republic of China (PRC) and the Calligraphy Title Appraisal Committee strictly rated Cao as a national first-class calligraphy master, with the approval number of W(20 1836 17986788).
According to the appraisal standard, the market price of calligraphy works is 60,000 yuan ~ 88,000 yuan/square foot, which is in line with the market value law of China artworks.