But more and more specialists are returning for home advantages

Sun Zhipei has only been in Helsinki for four months, but he has already decided it is where he wants to settle.

The 35-year-old nanotech scientist previously spent almost 10 years living in Spain and Britain, and said he would not entertain the idea of returning to his native China.

"I can have more control about what I want to study here and carry out projects I'm interested in," said the associate professor at Aalto University, who gained his PhD at the Chinese Academy of Sciences' Institute of Physics.

Sun's attitude perhaps goes some way toward explaining a People's Daily report in June that said China is experiencing "the world's worst brain drain".

Eighty-seven percent of the mainland's top specialists in science and engineering who went abroad for work or study have no plans to return, the paper quoted an unnamed official with the Party's coordination group on specialists as saying.

The group consists of 20 Party and government agencies, including the Organization Department of the Communist Party of China's Central Committee, which oversees human resources.

China Daily interview requests with the organization department went unanswered.

Although independent experts and statistics do not confirm the severity of the brain drain, there is little doubt it exists.

Wang Huiyao, director-general of the Center for China and Globalization, a Beijing-based think tank, said since the reform and opening-up policy of the late 1970s, 2.6 million Chinese students have studied overseas, of which about half went to the United States.

The US is also the No 1 destination for many Chinese students, he said, with more than 190,000 on campuses last year.

Meanwhile, US Department of Homeland Security data show about 32,000 people from the Chinese mainland became naturalized US citizens last year, while 82,000 received green cards.

Cao Cong has published several essays and books about brain drain issues, and is an associate professor of social sciences at the University of Nottingham in Britain.

He estimates that 90 percent of Chinese students who get a PhD in the US choose to settle down there.

But why are the mainland's top scientists and engineers so reluctant to return home?

"Chinese institutions have new research equipment, much of it better than at places in the US," said Joseph Jen, former undersecretary for research, education and economics for the US Department of Agriculture.

"I would say the most important reason good Chinese scientists choose to stay in the US is because of the scientific culture ... (in which) scientists have bigger freedoms to pursue research of their choice.

"In the US, graduate students are trained to be independent and innovative," said the 74-year-old, who was born in Chongqing but later settled in the US, earning a PhD in biochemistry at the University of California.

"In China, barring some exceptions, students are instrument operators, without opportunities to develop independent thinking and new creations."

Jen said he also believes that getting the best jobs in China still requires guanxi, or good connections, which is not the case in the US.

However, he conceded that although the US has material advantages, "racial discrimination still exists, and many Chinese-Americans are bothered by that."

Chen Zhengyu, an MBA student at Cambridge University's Judge Business School, said most of his Chinese friends who are professionals or scientists stay abroad for their children's education.

"It is a significant factor for Chinese parents to settle in Europe," he said, adding that many people want an alternative to a model focused on exam scores.