Recent increases in the number of births in New Zealand have resulted in headlines proclaiming the arrival of a 'baby boom' but is this proclamation valid?
The baby boom is a phrase commonly used by demographers to describe the large numbers of people born in the period following World War II. As such, it describes an historical period more than a demographic phenomenon. However, that won't help us answer the current question. So, for argument's sake, let's define a baby boom as 'a significant increase in the birth rate.'
There were 62,362 births in the September year 2007; that is the highest number of births since 1972 (64,090). What about the birth rate? The total fertility rate for 2007 was 2.1 births per woman. Although this is the highest rate since 1992, it is only 0.1 of a baby higher than the average birth rate for the last twenty years (2.0 births per woman).
In 1972, the birth rate was around 3 births per woman and the population was around 2.9 million compared with the current 4.2 million. If the 1972 birth rates applied today we would have had around 87,000 births in 2007.
With the current birth rate only just reaching replacement level (2.1) it is hard to justify the claim that New Zealand is having a baby boom.
Conclusion: this myth is busted
How did this myth arise?
The birth rate has been relatively stable over the last couple of decades. Fluctuating around 2 births per woman with a high of 2.2 in 1990 and a low of 1.9 in 2002. This period of stability may overemphasise the ups and downs. In contrast, the period from 1968 to 1987 saw a significant decline in the birth rate – from 3.3 births in 1968 to 1.9 in the early 1980s.
The highest number of births registered in a December year was 65,390 in 1961. At that time the birth rate was 4.3 births per woman.
Replacement level fertility is the average number of children a woman needs to have to produce one daughter who survives to childbearing age. It is also described as the total fertility rate required for the population to replace itself, without migration.The internationally accepted replacement level is 2.1 births per woman. It allows for the mortality of females between birth and childbearing and the birth of more boys than girls. On average, throughout the world, 105 boys are born for every 100 girls.
Provided by Statistics New Zealand, 17 December 2007.