Playing with numbers

SCMP July 24 2007

 

The quality of our census data is excellent, but population projections leave a lot to be desired, writes Philip Bowring

It is time the population projections of the Census and Statistics Department came in for some thorough scrutiny. These things matter deeply to the community at large, with regard to budgeting for infrastructure, housing, health, and the like. While demographic projections are always at the mercy of the unknowable, Hong Kong's have such a consistent bias to exaggeration that there must be some question as to whether they are influenced by the dreams of planners and a development industry which provides high-paying jobs to ex-civil servants and chiefs of police.

Although there can be few doubts about the quality and accuracy of the data the department collects and publishes, its projections are another matter altogether.

It should never be allowed to forget its action in 1999 of tearing up its former estimates and devising a ludicrous number - 1.7 million - of supposed mainland offspring of Hong Kong residents who were going to flood the city and its schools, as a result of the Court of Final Appeal ruling on the right of abode. This dishonest concoction was then used to try to scare the public into accepting the government's undermining of Hong Kong's autonomy by going to the National People's Congress to overturn the ruling.

The latest population projections certainly do not fall into that league of politically motivated fiction. But the department still seems to be straining to get the kind of population growth numbers that would move us towards the magical 10 million figure that Donald Tsang Yam-kuen feels is necessary for Hong Kong to be the equal of New York or London.

But, first, a little population-projection history. This is the fourth such projection in the past 10 years. According to one in 1997, by mid-2006 (the base year for the latest estimates), Hong Kong was supposed to have a population of 7.38 million. The next estimate, in 2000, reduced that to 7.24 million and the 2004 projection to 6.94 million. In reality it was just 6.85 million.

Likewise, longer-term estimates have been consistently reduced - that for 2011 from 7.79 million in 1997 to 7.15 million now; that for 2016 from 8.2 million to the latest figure of 7.45 million; and that for 2021 from a 2000 estimate of 8.49 million, to the latest one of 7.78 million.

These are huge differences in the context of urban and social planning. Some things are indeed unpredictable. But one thing is fairly constant - numbers. While projections are never easy, some items are reasonably predictable. Those arriving on one-way permits from the mainland, the biggest single factor in population change, are stable and controlled by the government. Birth rates change only quite slowly, and longevity rates even more slowly.

But instead of dealing with current realities, the department has shown a tendency to second-guess changes in a way which exaggerates its future population estimates. For example, its 1997 projections took the view that fertility rates would rise gradually from about 1.0 births per woman to about 1.48 by 2011. Of course, fertility rates can go up as well as down, as they have indeed done in several European countries. But Hong Kong's has stuck at about 0.95.

The latest population numbers for the future may be down on previous estimates, but they are still surprisingly high. The five-year annual average growth is now forecast to double, from 0.4 per cent to 0.8 per cent, despite the ageing population and very low birth rate. The department now assumes that fertility rates of Hong Kong women will not, after all, rise appreciably. So, it is having to look elsewhere to get the increase in the population that it is now forecasting.

Its answer: suppositions about mainland women coming here to give birth. This is particularly bizarre given that government policy is to deter people from coming to give birth, whether to acquire right of abode for their offspring or because of the quality of public health care.

It is also apparently successful. The South China Morning Post reported in May: 'The number of mainland mothers admitted daily for emergency births has dropped nearly 80 per cent since measures were introduced in February. Acting deputy director of immigration David Chiu Wai-kai told legislators that an average of five non-local women a day were arriving at accident and emergency units in public hospitals compared with about 25 in February and March last year.'

Yet there is still an expectation that the total number of births will rise from 60,000 last year, to 69,000 this year, and then stabilise at about 70,000. With local fertility stagnant, this assumes that births to mainland women whose spouses are not Hong Kong permanent residents will rise from last year's 16,044 to some 25,000.

The department then goes on to assume that, though most of these babies will go back to the mainland soon after birth, no less than 55 per cent will return to Hong Kong by the time they reach 21!

In other words, a significant part of the assumed population rise is predicated on mainland mothers continuing to come in very large numbers, and of their progeny returning to Hong Kong as permanent residents.

A less contentious but possibly more disturbing figure in the projections is that the gender gap will continue to widen, and by 2016 there will be 9 per cent more women than men, and in the 20-34 age group there will be 1,021 women to 732 men. That is partly explained by an assumed rise in the number of domestic helpers, but partly too by local men marrying mainland, rather than local, women. Meanwhile, on the mainland, there will be roughly 115 men for 100 women in that age group.

There are many pitfalls in any projections, but let us not be carried away by distorted expectation into justifying more pouring of concrete, more bridges to nowhere and more projects to satisfy the egos of ministers. Scrutinise those numbers, please.

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