Since the study mentioned/focused on Hong Kong, this is from Wikipedia. PISA was the one mentioned in the study. It seems that there are few true government run schools.
Hong Kong's education system used to roughly follow the system in England, although international systems exist. The government maintains a policy of "mother tongue instruction" (Chinese: 母語教學) in which the medium of instruction is Cantonese, with written Chinese and English. In secondary schools, 'biliterate and trilingual' proficiency is emphasised, and Mandarin-language education has been increasing. The Programme for International Student Assessment ranked Hong Kong's education system as the second best in the world. Hong Kong's public schools are operated by the Education Bureau. The system features a non-compulsory three-year kindergarten, followed by a compulsory six-year primary education, a compulsory three-year junior secondary education, a non-compulsory two-year senior secondary education leading to the Hong Kong Certificate of Education Examinations and a two-year matriculation course leading to the Hong Kong Advanced Level Examinations. The New Senior Secondary academic structure and curriculum was implemented in September 2009, which provides for all students to receive three years of compulsory junior and three years of compulsory senior secondary education. Under the new curriculum, there is only one public examination, namely the Hong Kong Diploma of Secondary Education.
Most comprehensive schools in Hong Kong fall under three categories: the rarer public schools; the more common subsidised schools, including government aids-and-grant schools; and private schools, often run by Christian organisations and having admissions based on academic merit rather than on financial resources. Outside this system are the schools under the Direct Subsidy Scheme and private international schools.