The home truth: we suck at maths, and we don’t need that many flats in Hong Kong

PUBLISHED : Thursday, 12 November, 2015, 2:28pm
UPDATED : Monday, 16 November, 2015, 4:43pm

One of this town’s oddities is how its students regularly score tops on international mathematics tests and yet many of them cannot cope with even the simplest numbers when they get out of the classroom.

Take the projections made by this researcher from former chief executive Tung Chee-hwa’s Our Hong Kong Foundation, a Beijing loyalist political front masquerading as a think tank.

[Foundation researcher William Tsang Wai-him] added that Hong Kong’s population could expand to 8.22 million in the next three decades, so the government would need more than 9,000 hectares of land, or three times the size of Sha Tin new town.

A land area of 9,000 hectares is 90 square kilometres, greater than all of Hong Kong Island, which has a land area of only 78.6 square kilometres. It amounts to 8.2 per cent of the total land area of Hong Kong.

Just imagine walking around 9,000 hectares. You tie up your hiking boots and you set off for 10 km. You then do a 90 degree turn and you walk another 9 km. Then you do 10 km again and finally another 9 km and someone gives you a medal as you drop down at the finish line. We’re talking a lot of land.

Now let’s do some more numbers. Our population as of the June half-yearly estimate was 7,298,600 and the foundation works with the official Census and Statistics forecast of 8.22 million in 2045. The forecast increase in population therefore comes out to 921,400 people.

We now take 90 sq km, which equals 90 million square meters, and we divide by 921,400 people. This gives us 97.7 square meters or 1,051 square feet of land for each additional member of the population. Not bad, huh.

But we’re not finished. Let’s assume an average plot ratio of 5 times. In other words, the gross floor of each new residential building will be five times the land area given to that building. It is normally a higher ratio but we make allowances here for public space. We now have 5,255 square feet of floor space per person.

Lastly we remember that our average household size is 2.9 persons at present. We now have an average home size of 15,399 square feet for each of the new households that Mr Tung’s foundation envisages.

Which is about 25 times the size of the average home.

Back to arithmetic class for someone, wouldn’t you say?

We have more yet. Another oddity of this town is the wide margins by which our bureaucrats routinely overestimate future population numbers.

The chart shows you the trend. The only line on which you can roughly rely here is the irregular blue one on the bottom left hand side of the chart. This represents the actual census population count since 1997.

Now we turn to the three lines that trend sharply up on the left hand side of the chart. These represent the high, medium and low forecasts of the Third Comprehensive Transport Study (CTS3) in 1999. Someone actually thought we might have 10.3 million people by next year. Stop laughing.

Bear in mind also that this study’s projections have never been withdrawn. They are still the basis of our transport infrastructure spending.

Closer to reality are the Census and Statistics (C&S) projections in 2010, 2013 and lastly 2015. But note that all of these in turn have had to be reduced from previous projections. Note also that the 2015 projection assumes that 8.2 million people in the mid-2040s will be a peak and population numbers will then decline.

Given the invariable record of over-projections in the past, however, it is unlikely that we will even get to 8.2 million.

Think tanks!