Statisticians have put years of quiet preparation into the decennial population survey next March. The results will help the Government plot the way ahead
COUNTING may be an easy task for many, but to figure out the exact size of the population in a city or a state is certainly an art. Many countries spend several years completing a population census, just to obtain up-to-date benchmark information on the demographic and socio-economic characteristics of the population, and its geographical distribution.
Such information is vital to governments for planning and policy formulation.
Hong Kong is already much better off than most developing countries, as our central registry is well-established. The Government has a complete set of records on our births, deaths and marriages. Also, immigration records show mobility trends.
But still, to conduct a population census in the SAR involves complicated techniques. The census, taken every decade, will be held from March 15 to 27 next year. One-seventh of households surveyed will undergo a detailed interview, with the remainder being asked to provide basic information.
Dr Frederick Ho Wing-huen, the Commissioner of Census and Statistics, has been doing this job for more than 28 years, and has been in charge of organising the upcoming census since 1992.
The first decision to be made in the big study is the establishing of a census reference point. Everyone will be asked their whereabouts at a particular time. This time, or reference point, will be set at March 14, 2001, at 3am. 'This is the most static hour, as most people are asleep,' Dr Ho says.
Yet thousands of people will, nonetheless, be away from their homes at the crucial moment. 'How about those who are playing mahjong overnight outside or working on night shifts? We have to draw a line on this sort of thing.'
People playing mahjong, working or otherwise away from home will, although somewhere else at the specific time, be recorded as living at the location of their homes. But there are more questions to come.
'How about a grandmother who has two homes, sharing her time between the residences of her children. Then we need to ask where she stays longer, and if she can't give a clear answer, we will determine her permanent residence by the place where she was at the reference point. We have to be careful on every single small point, otherwise the whole thing will be a mess.'
The census, in theory, includes everyone in the city. However, many people, such as those travelling overseas, will be out of the survey's reach. This will undermine the Government's goal of determining the size of mobile population, a figure which is increasingly important as more and more people choose to live on the mainland.
For the first time, the department will integrate the census results with immigration records. 'We will mix them together and get a clearer scenario,' Dr Ho says.
And so the study can begin. Carrying out a population census is like launching a massive campaign. A total of 23,000 teachers and students will be hired part-time to conduct the survey and 70 per cent of primary and secondary students will enjoy a two-week holiday.
After a training session of between seven and eleven hours, the census workers will be sent to conduct the interviews.
All census workers are by law required to keep the information collected confidential. Under the same legislation, all residents in Hong Kong are obliged to give details.
'This privacy concern is important,' Dr Ho says. 'We cannot allow people to publicise information about the home of a movie star, for example, even though the students [interviewing the celebrity] would feel very excited.'
Getting a completed survey form is often not easy. Alvin Li Wing-kong, assistant commissioner of Census and Statistics, says: 'We can never get a completed questionnaire by knocking on the door just once. On average, we need to visit a household two or three times to get in touch with all family members.'
Then there is the decision as to which questions to ask. Basic questions, put to all households - such as the occupant's sex, age and marital status, and the size of the household - are asked every time, but others will vary according to changes in society.
For example, in the 1970s the Government asked citizens about their place of origin or their home town because at that time Hong Kong was still a city with a large number of mainland immigrants.
Now, it asks about their nationality instead, as more and more people are foreign passport holders.
Some questions are deleted because of the difficulty in getting reliable answers. The census next year will not ask about the duration of residence in the present district, because many people have lived there too long to be able to remember when they arrived.
New questions are added this time to facilitate government reforms and new developments. The study will ask about the highest level of education people have completed to assist ongoing education reforms, and also their mode of transport to work in order to aid research for future railway projects.
The administration will also try to learn more about people's standard of living, by asking about their mortgage repayments and the number of rooms in their residence.
But Mr Li says there are still limitations on this kind of question. 'We don't know exactly how big the flat is in which people are living. There could be three bedrooms in a tiny apartment.'
Also, the survey will ask for the first time about people's ethnicity. Dr Ho says this could be sensitive, as some people may not want to reveal their ethnic origin. 'In addition, some people with mixed race may not know exactly their ethnic origin,' he adds.
But there is a limit on the number of questions in a survey. The length of the survey form has been increasing, from 31 items in 1971 to 41 next year.
'We received all kinds of questions when we did the consultation among government departments,' Dr Ho says, 'but this is about the upper limit. People will get impatient if they are asked to spend more than 25 minutes.'
So some questions have been removed, such as those concerning residents' part-time jobs and their working hours. These are instead included in the smaller-scale General Household Survey.
Dr Ho says the data collected is to be used by the Government for different planning and policy purposes, and it has tried its best to get the most reliable and useful figures.
He says the results should provide the authorities with much food for thought.
'I just hope this [food for thought] will be a very rich buffet meal.'
Quinton Chan (email@example.com) is a staff writer for the Post's Editorial Pages