Scientists of Chinese descent in the United States have been leaving the country because of "pull factors" from China and the "push factor" of the China Initiative of 2018, according to a major research study published in an American scientific journal.

The trend suggests a reverse brain drain, and the data used for the analysis is extensive.

The study, published in the Proceedings of the National Academy of Sciences, used Microsoft Academic Graph to analyze trends in the migration of US-based Chinese scientists between 2010 and 2021.The database tracks more than 200 million scientists from over 25,000 institutions worldwide.

Also, a brief on the study, published in July by the Stanford Center on China's Economy and Institutions, concluded that the discontinued China Initiative "provided scientists of Chinese descent in the US with higher incentives to leave and lower incentives to apply for federal grants".

The purported objective of the China Initiative — launched by the Justice Department under the Trump administration and halted in 2022 under the Biden administration — was to reduce economic espionage.

The study identified the working countries of researchers through their academic affiliations in publications and tracked those with Chinese surnames who initially published in the US but later changed their affiliations to institutions abroad.

The study identified 19,955 scientists of Chinese descent who began their careers in the US but left for other countries, including China, between 2010 and 2021.

The researchers said that contributing to the trend were "pull factors" from China, including the country's large and rapidly growing investments in science, high social prestige, and attractive financial rewards connected to positions in Chinese institutions.

But the analysis also showed a "push factor" in the US. Following the implementation of the China Initiative, departures of US-based, China-born scientists increased by 75 percent, the study found.

The data showed that as of 2021, of those leaving the US, the percentage of scientists moving back to China increased to 67 percent, up from 48 percent in 2010. The life sciences field witnessed the most significant exodus abroad, with more than 1,000 life scientists leaving in 2021.

The researchers also conducted an online survey of 1,304 US-based scientists of Chinese descent between December 2021 and March 2022 to find out why more were leaving.

The survey results revealed the chilling effects of the China Initiative. About 35 percent of Chinese scientists in the US said that they felt unwelcome; 72 percent didn't feel safe as academic researchers; 42 percent were fearful of conducting research; and 65 percent were worried about collaborations with China.

Of the five possible reasons for "not feeling safe as an academic researcher in the US", the foremost reason cited by the respondents-67 percent of them — was fear of "US government investigations into Chinese-origin researchers".

About 45 percent of respondents said that they now avoid federal research grants, and 61 percent said that they had considered leaving the US.

MIT professor Gang Chen, who had espionage charges slapped on him under the China Initiative only for them to be dismissed in 2022, said publicly that after undergoing the lengthy legal process that damaged his reputation and forced many of his students to adjust their career paths, he was avoiding federally funded research out of fear.

Students from China have been an important source of US-based scientists for more than two decades. The study said that in 2020, of all US doctoral degrees in science and engineering, 17 percent — roughly 5,800 of 34,000 — went to foreign students from China, and the vast majority of those had chosen to stay in the US in previous years.

"It's unfortunate that the China Initiative has turned out to be a government-sanctioned persecution of people of Chinese heritage," a STEM(science, technology, engineering and mathematics) professor in Houston who spoke on condition of anonymity told China Daily. "The federal government was wrong to prosecute people primarily based on race. It is not a surprise that such a practice has created fear in the community."

An analysis by Race, Racism and the Law, a civil rights group, concluded that of the 148 defendants across 77 cases collected in the FBI database, 130-approximately 90 percent — were of Chinese heritage.

Only 25 percent of them were convicted, and few of the convictions were related to espionage. The conviction rate was dramatically lower than the Justice Department's 91 percent overall conviction rate.

In June, Marcia McNutt, the president of the National Academy of Sciences, said that while the US still spends the most money among any country on research and development, China is set to soon outpace those investments.