Dr. Eberstadt is a Henry Wendent scholar in political economics working basically on demographic and other such economic factors. He is a well learned person and he came forward with the concept we know as “four unexpected” surprises in his speeches and work. According to his views a lot of changes in the demographics of the world have laid down the foundation of these four unexpected surprises. According to his views the demographics and population studies differ in the way they relate or answer the basic questions, one being very minute and insignificant and the other being evasive enough to think there are no answers to it.
An idea put forward by Frank Milstein predicted of some of the future changes which were going to occur because of the changes in the knowledge and income of people. According to him with the increase of both these factor the rate of fertility and morality would be going through a severe and disastrous change. The first factor speaks about the fertility decline which would be seen in the people when their level of knowledge and income changes. It states how different countries are categorized as sub replacements today.
These are those countries according to the US Census Bureau, that have a continued child bearing pattern that if sustained as a trend would bring about stabilization and a counterbalance migration. There are many venues that are capable enough of calling them as a sub replacement fertility center, though the term being unfamiliar and unheard of among the new generation. It was first seen in the Europe and now Western Europe, Eastern Europe, Soviet Union, US, North America, China, Hong Kong, Japan, Thailand, Sri-Lanka and Caribbean is replacing sub replacement fertility.
It also mentions the consequences of sub replacement i. e. rapid aging of population. And the one who would be most affected by this consequence would be Japan. Soon by 2050 Japan would be having one out of nine people at the age of 80. The median being the age of 50. Furthermore Japan would be among the people who would be richer quite before they get old. But at the same time there are countries that would get old before they get rich.
China is considered to be the most important instance which is considered to have a low mortality along with low fertility all at the same time. Therefore comparing China with Japan, china would get old soon enough at a lower income level than Japan. Furthermore the pension plans in China tend to reach one sixth of the people which is very low. This means that if the Chinese people want to survive they need to earn for their living though being at the older age, at the same time knowing that the work in China is more labor oriented, which is a frail work for older people.