Measuring the heartbeat, vital signs and delivering a prognosis of a patient as diverse as Hong Kong cannot be easy. But Anthony Mak Shiu-kwai, senior government statistician, has been looking forward to the consultation for a long time. 'It is a service for the community,' he said. Yesterday, his small army of more than 7,000 mostly students began earning the $5,249 one-off fee for their labours. On foot, in vans and even in boats, and armed with trusty pens and folders bulging with forms, they are touring the territory to get answers from some 260,000 households for the 1996 bi-census. 'We will also have to use chartered transportation in addition to the various means of transport to get to different places or deliver materials to and from our field centres,' Mr Mak added. But 18-year-old 'enumerator' Chiu Wing-san worries about hostile and unco-operative householders as well as fatigue. 'I am not sure about how I will react if there is only me and a man in a flat,' she said. 'Our trainers have only stressed that everything will be alright.' Mr Mak sounded an extra note of caution, saying enumerators should beware of attacks by dogs at certain estates and in the New Territories. There have been cases of dog bites in the past, he notes, though none were serious. But there is no real cause for concern over the safety of the young enumerators: 'They are required to report their whereabouts to their team leader constantly. They go to each building in pairs and will be in contact with each other even though each visits a household alone.' He adds that it will mostly be boys who will visit remote places like Sha Tau Kok, knocking on doors from 10 am to 10 pm to gain a snapshot of people from all walks of life in the territory. Yellowing newspaper cuttings show that after the 1961 census, the boffins who boiled down the raw data concluded, among other things, that three boys and 11 girls under the age of 15 were married. Thirty years earlier, 1,365 reported being married before turning 15. Hong Kong's population stood at a little over three million in 1961. It is now more than six million. Locally-born Chinese were beginning to form a majority, making up 47.7 per cent of the total number of residents, compared with 32.5 per cent in 1931, with much of the rest made up of refugees from Guangdong. The average monthly salary was $5,170 in 1991 - a 241 per cent increase since 1981. And average household income had risen sharply, from $2,960 to $9,960. Comparisons of seemingly useless facts like these are grist for the mill of Mr Mak and his staff. The answers to census questions, including the salaries of households and the number of children they have, help both the public and private sector plan for the territory's social, economic and demographic future. Numerous private companies, such as the Mass Transit Railway Corporation and fast-food chains, use the information on population distribution in various districts, for example, when considering expansion. 'The same information is also useful for deciding on transportation policies,' Mr Mak said. 'Or the figures on the number and distribution of elderly people will have implications for social welfare policy.' The summary report to be released in November following this week's survey, for example, is expected to show an ageing Hong Kong. Reports on specific data are also due to be released over the next year. For the first time, this year's survey also looks at respondents' 'place of work' and 'place of study'. This, said Mr Mak, will provide extra information for business people and retailers: where most people are during the day. But despite the publicity surrounding the $185 million exercise, members of the vast majority of selected households - drawn from the territory's registers - have little idea about its importance, except that they are fulfilling a civic duty. One 39-year-old housewife, Lam Wai-chun, is frank about her ignorance. 'I really don't know what the collected data will be used for,' she admitted. 'Neither do my neighbours who have been selected for the surveys. 'All I know is my teenage daughter doesn't have to go to school while the census is on. I wonder if people are willing to reveal their personal information to an outside person. Many like to have privacy.' Mrs Lam and thousands of others can also expect to be asked questions like the language she speaks, length of residence in Hong Kong and in the district. Altogether, 26 sets of questions on personal data are included in the survey, plus five for heads of households. Unknown to her is that all those selected are required by law to respond to the questionnaire or they will be fined as much as $500. Even prisoners and street sleepers will be counted, but by Correctional Services and Social Welfare officers rather than students. After all, a census should represent a cross-section of society. Mr Mak is pinning high hopes on the massive project. It is being held in the middle of the inter-censal period to collect detailed characteristics on a smaller sample than a full census that, since 1961, has only been held once a decade. But one concern over this year's survey relates to the use of the collected data. Given the approach of 1997, human rights activist Ho Hei-wah has expressed worries about the leaking of sensitive information such as one's nationality. He has demanded close monitoring of the use of the data. 'We have to control very strictly how the information is used and who has access to the information,' he said. The Government has pledged to shred all personal details a few months before the handover. Mr Mak has stressed that only his department will have access to the personal information. Furthermore, he says, respondents are not required to give their full name in the surveys. Neither will their full address be placed on record. Regardless of the various concerns, the bi-census is no doubt a valuable exercise. The statistics obtained as a result reflect the changing nature of our society.