While the reasons behind China's detention of Hong Kong academics Li Shaomin and Xu Zerong remain a mystery, their cases have highlighted the risks and challenges of doing research on the mainland. Local universities offer no guidelines for academics on research trips in China, and university representatives said that had not changed despite the arrests. But the arbitrary manner in which arrests can be made in China is of serious concern to some academics. Since the detentions, Anhui native X L Ding, now teaching at the Hong Kong University of Science and Technology, has deferred his plans to carry out studies on economic reforms in China this year. 'There are no unifying, explicit rules on how academics should go about doing research in China,' said Dr Ding, an expert on mainland economic reform. When on the mainland, he only conducted interviews and rarely sought out official data, which he dismissed as propaganda. 'It's a pity I'm not going there for my research, but that's life - life is full of regrets,' he said. A Hong Kong-born veteran researcher at the Chinese University said some academics here had exercised more caution and become more selective in their research topics since 1997. 'They have gone back less frequently to China since the handover,' he said. 'They are more careful now in doing more sensitive topics - they never know when they will hit a landmine as the political climate changes.' But such increasingly cautious attitudes could be taking a toll on the quality of research on China. 'They may eventually lose sensitivity to important issues in China,' said the academic, who was unwilling to be named. Beijing has confirmed the arrest in late February of Dr Li. There have been reports that Dr Xu was arrested by agents of China's Ministry of State Security last year, after the publication of an article he wrote on Chinese aid to the Malayan Communist Party between 1960 and 1980. Beijing has not made any comments on those reports and is tight-lipped about the two academics' whereabouts. Dissident writer Liu Xiaobo said there could be a deliberate neglect of sensitive subjects - such as the Cultural Revolution, the pro-democracy student protests in 1989 and the disastrous Great Leap Forward movement in the 1950s - by academics fearing for their safety. 'It's unfortunate - without research, the truths of big tragedies that happened in the past will never be known,' said Mr Liu. 'No lessons will be learned to avoid similar tragedies.' Mr Liu, a former teacher at Beijing Normal University, led a hunger strike among intellectuals in support of the student democracy protesters in 1989, and was jailed for 18 months. He now spends his time writing articles for magazines and newspapers in Hong Kong and Taiwan. His views are backed by leading Australian sinologist and author Jeremy Barme. 'Those who work on subjects such as birth control, corruption and political sciences will be most vulnerable to government pressure,' said Mr Barme. 'Each case is different, depending on one's relationship with the local authorities.' Academics from inside and outside China face onerous bureaucratic procedures when they want to carry out interviews with officials or state employees, or seek to collect information from government bodies. Sometimes, according to one local academic, they have an even harder time than journalists in getting access to what they want. 'It takes a very long time before you can get permission to carry out research there,' said Lingnan University politics associate professor Ren Yue, who specialises in China's foreign policy. 'There is bureaucracy in every country, but in China, because of the issue of political sensitivity, it is more difficult for overseas scholars to gain access to information there.' The lack of transparency in China means scholars often have no idea where to get what they want, even if the information they are after is not confidential. That makes it all the more important and advantageous for people doing research on China to have good connections there. Given their strong links with prominent mainlanders, who perhaps were childhood friends, academics originally from China have had greater success in producing acclaimed work than their Hong Kong-born counterparts. Dr Ren, a native of Xinjiang who undertook his postgraduate studies in the United States, said he resorted both to applying through official channels and obtaining information from contacts. His patience and skills in digging up information and cultivating long-established ties have paid off. The Hong Kong-based China researcher is also a friend of the two missing academics. Dr Li is an American citizen who teaches at City University's marketing department, and Dr Xu a Hong Kong resident who teaches at Guangzhou's Zhongshan University. But despite Dr Li and Dr Xu's summary detention, Dr Ren remains undeterred. 'As an academic, you know what your bottom line is,' he said. 'I tell my contacts not to give me any classified information. I don't want to jeopardise the interests of any of them.' He shared the view of other mainland academics in Hong Kong that the pair had not been detained due to their publications. 'I've seen other articles in mainland publications that carried more sensitive information,' he said. 'What was covered in Dr Xu's article was an open secret.' University of Hong Kong Centre of Asian Studies researcher Gan Yang was also set to carry on. 'I don't need classified documents to do my research,' he said. 'I see a lot of things when I am in China. I read mainland publications and there is loads of information on the Net.' Graphic: ACADGAN