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[h=1]The White Paper uses ‘Rojak’ TFR to justify immigration policy[/h]
The Population White Paper recommends immigration as a means to make up for population shrinkage due to our low total fertility rate (TFR) of 1.2. In a letter to the Straits Times [1], Mr Ng Ya Ken makes a similar calling for us to find the ‘true’ reason for its formulation, which is our ‘dire’ demographic situation if foreigner intake is insufficient. It is Mr Ng’s hope that those who can see the ‘big picture’ help the rest see it.
The so-called ‘big’ picture rests on a single number – TFR of 1.2 in 2012. The TFR for any particular year is obtained by adding up the age-specific fertility rates for that year (and then dividing by 200) as shown in the table below.
The problem with this approach is that we end up with a ‘rojak’ TFR that combines the fertility of women from different generations at different stages of their fertility cycle. This ‘rojak’ TFR doesn’t reflect the fertility of any particular generation of women. To find out the fertility of any particular generation of women, we need to trace its fertility diagonally downwards across years. To do so more easily, we can align the age-specific fertility rates according to generation to create the table below which shows the ‘true’ TFR for each 5-year generation of women.
The importance of aligning age-specific fertility rates to obtain the ‘true’ TFR can be illustrated with an example. If we refer to the original, non-aligned TFR table, the ‘rojak’ TFR for 1985 is 1.59. But when we refer to the new, aligned TFR table, the generations of women that contributed to the ‘rojak’ TFR of 1.59 had ‘true’ TFRs ranging from 1.72 to 2.29, all higher than 1.59. Herein lies the problem with the ‘rojak’ TFR: it may not give a true picture of the fertility of our women. In a society where marriage and child bearing are being delayed, the bulk of the children of the younger generations of women may only come much later but this contributes to a lower ‘rojak’ TFR now. At the same time, the older generation of women who already had the bulk of their children earlier will also similarly contribute to a lower ‘rojak’ TFR now. The way to avoid all these distortions is to make use of the ‘true’ TFR instead.
The ‘true’ TFR approach is only available for those generations that have completed their fertility life cycles. These have to be extrapolated to obtain the ‘true’ TFRs of future generations. The following tables show the ‘true’ TFR data points of women who turned 15 between 1963 and 1987 (that means born between 1948 and 1972) and then extrapolated for another 73 years to the year 2060. Two models of extrapolation are used here: the log model and the power model (both provided by Excel). We can see that in the case of the log model, our true TFR hasn’t reached 1.2 yet even at year 2060. For the power model, our true TFR is about 1.4 at year 2060. Both models show that our true TFRs are far from as dire as our ‘rojak’ TFR suggests.
It is worrying that our nation is being huddled along in accordance to a number that may not even reflect the true picture, let alone big picture. Previous governments have experimented with population control and ended up being off by a mile. Is the present government so much more prescient that they will not be off by more than a mile?
Thank you.
.
Ng Kok Lim
[1] Straits Times, 19 Feb 2013, Help people see the big picture
The so-called ‘big’ picture rests on a single number – TFR of 1.2 in 2012. The TFR for any particular year is obtained by adding up the age-specific fertility rates for that year (and then dividing by 200) as shown in the table below.
The problem with this approach is that we end up with a ‘rojak’ TFR that combines the fertility of women from different generations at different stages of their fertility cycle. This ‘rojak’ TFR doesn’t reflect the fertility of any particular generation of women. To find out the fertility of any particular generation of women, we need to trace its fertility diagonally downwards across years. To do so more easily, we can align the age-specific fertility rates according to generation to create the table below which shows the ‘true’ TFR for each 5-year generation of women.
The importance of aligning age-specific fertility rates to obtain the ‘true’ TFR can be illustrated with an example. If we refer to the original, non-aligned TFR table, the ‘rojak’ TFR for 1985 is 1.59. But when we refer to the new, aligned TFR table, the generations of women that contributed to the ‘rojak’ TFR of 1.59 had ‘true’ TFRs ranging from 1.72 to 2.29, all higher than 1.59. Herein lies the problem with the ‘rojak’ TFR: it may not give a true picture of the fertility of our women. In a society where marriage and child bearing are being delayed, the bulk of the children of the younger generations of women may only come much later but this contributes to a lower ‘rojak’ TFR now. At the same time, the older generation of women who already had the bulk of their children earlier will also similarly contribute to a lower ‘rojak’ TFR now. The way to avoid all these distortions is to make use of the ‘true’ TFR instead.
The ‘true’ TFR approach is only available for those generations that have completed their fertility life cycles. These have to be extrapolated to obtain the ‘true’ TFRs of future generations. The following tables show the ‘true’ TFR data points of women who turned 15 between 1963 and 1987 (that means born between 1948 and 1972) and then extrapolated for another 73 years to the year 2060. Two models of extrapolation are used here: the log model and the power model (both provided by Excel). We can see that in the case of the log model, our true TFR hasn’t reached 1.2 yet even at year 2060. For the power model, our true TFR is about 1.4 at year 2060. Both models show that our true TFRs are far from as dire as our ‘rojak’ TFR suggests.
It is worrying that our nation is being huddled along in accordance to a number that may not even reflect the true picture, let alone big picture. Previous governments have experimented with population control and ended up being off by a mile. Is the present government so much more prescient that they will not be off by more than a mile?
Thank you.
.
Ng Kok Lim
[1] Straits Times, 19 Feb 2013, Help people see the big picture
THE Population White Paper is unpopular because its projections go against our natural instincts and sentiments (“Positives from the population debate” by Mr Viswa Sadasivan; last Friday).
To discuss it with rationality, we have to go deeper to find the true reasons that prompted its formulation.
One good source to revisit is the population projections by the Institute of Policy Studies (IPS) in September 2011 (“Population will shrink without immigrants”; Sept 8, 2011). Its study showed how dire our demographic situation would become in future decades if there is insufficient intake of foreigners.
With hindsight, population planning should have been carried out in three stages.
In stage one, we should discuss our long-term population trends, in particular, how to prevent Singapore from becoming a “retirement village”.
Five or six of the IPS’ “middle-path” scenarios, and some extreme ones, could be used for comparison. These scenarios were derived based on different assumptions of new births and intake of foreigners.
Give more time for the people to digest and discuss these consequences caused by low fertility rate and the fast-ageing population.
A deeper understanding of these trends and implications would help us realise the need to allow our population to grow, including from more births.
In stage two, we could focus on two or three middle-path scenarios and compare their various implications on the workforce, public expenditure, taxation, housing, transport, land use, environment, water and energy requirements and so on.
We could then discuss which scenario would give us the most acceptable balance between benefits and costs in 20, 30, and 40 years’ time, and see how much inconvenience we are willing to tolerate.
Policymakers would then decide on one or perhaps two scenarios to use for drafting the White Paper.
In stage three, we should discuss boosting births, building infrastructure, and improving the environment and quality of life, as well as tackling problems brought on by a larger population with more foreign-born people.
We should fine-tune the model if needed.
The Government could have done more to help people visualise our future demographic challenges, and assist them in organising the bits and pieces of information together to see the total picture.
I hope those who can see this big picture help the rest to see it.
Ng Ya Ken
Posted by Ng Kok Lim on April 10, 2013.To discuss it with rationality, we have to go deeper to find the true reasons that prompted its formulation.
One good source to revisit is the population projections by the Institute of Policy Studies (IPS) in September 2011 (“Population will shrink without immigrants”; Sept 8, 2011). Its study showed how dire our demographic situation would become in future decades if there is insufficient intake of foreigners.
With hindsight, population planning should have been carried out in three stages.
In stage one, we should discuss our long-term population trends, in particular, how to prevent Singapore from becoming a “retirement village”.
Five or six of the IPS’ “middle-path” scenarios, and some extreme ones, could be used for comparison. These scenarios were derived based on different assumptions of new births and intake of foreigners.
Give more time for the people to digest and discuss these consequences caused by low fertility rate and the fast-ageing population.
A deeper understanding of these trends and implications would help us realise the need to allow our population to grow, including from more births.
In stage two, we could focus on two or three middle-path scenarios and compare their various implications on the workforce, public expenditure, taxation, housing, transport, land use, environment, water and energy requirements and so on.
We could then discuss which scenario would give us the most acceptable balance between benefits and costs in 20, 30, and 40 years’ time, and see how much inconvenience we are willing to tolerate.
Policymakers would then decide on one or perhaps two scenarios to use for drafting the White Paper.
In stage three, we should discuss boosting births, building infrastructure, and improving the environment and quality of life, as well as tackling problems brought on by a larger population with more foreign-born people.
We should fine-tune the model if needed.
The Government could have done more to help people visualise our future demographic challenges, and assist them in organising the bits and pieces of information together to see the total picture.
I hope those who can see this big picture help the rest to see it.
Ng Ya Ken
