First-born children do best regardless of the size of the family.
Kjell G. Salvanes
Being born last can come at a cost
The youngest siblings tend to do worse than their older brothers and sisters. Less education and lower earnings are among the consequences of being born last.
Twenty years ago, NHH professor Kjell G. Salvanes , Sandra Black and Paul Devereux conducted a study on families and birth order.
This week, a new scientific article by other researchers was published. They, too, have examined the same phenomenon.
`The pattern is exactly the same,´says the professor at the Department of Economics and Deputy Director of the Norwegian Centre of Excellence FAIR.
The findings from 2005 challenged earlier research claiming that family size is what determines children’s future outcomes.
Birth order
There is, after all, a tendency for children from large families to have less education than children from small families.
The study The More the Merrier? (see fact box) showed that it was not family size that mattered most, but birth order.
`First-born children do best regardless of the size of the family. The children who follow do gradually worse. And this does not apply only to education — both earnings levels and the likelihood of having full-time work decline in step with the child’s number in the birth order,´ says Salvanes.
Children number four and five have, on average, one year less education than child number one. The study also showed that women born last are more likely to become teenage mothers than their first-born sisters.
It is well established that teenage mothers tend to do worse in education and in the labour market.
`That was a very strong result,´ says Salvanes.
New study: Germs in the Family
The research attracted major international attention. It is widely cited in academia and has been covered in a number of media outlets, including this week. The new study Germs in the Family was mentioned in The Economist, which this headline plays on.
The oldest child gets more one-on-one time with the parents.
Kjell G. Salvanes
The “germs study” explores what may lie behind these differences:
Do parents behave differently towards the youngest child — or could younger children simply be more exposed to infection and illness than first-borns?
`not doing anything wrong´
`When we published our scientific article, we pointed to two possible explanations. One is fairly mechanical: parents spend less time on the youngest child. The oldest child gets more one-on-one time with the parents,´ he says.
He still believes this is a central part of the explanation.
`Parents only have a certain amount of time. They can spend more time alone with the oldest child. When number two arrives, and later number three and four, there is less time for each. We found a fairly even gap between one and two, two and three, three and four — within the same family size,´ says Salvanes.
At the same time, he stresses that this does not mean parents are doing anything wrong.
The More the Merrier?
The More the Merrier? The Effect of Family Composition on Children's Education, published in Quarterly Journal of Economics (2005). By Kjell Gunnar Salvanes, Sandra Black og Paul Devereux. It is based on census and register data and includes large parts of the Norwegian population from 1912 to 1975.
`It is about the structure of everyday life, how time is spent, and the realities of life in families with small children.´
The second explanation the researchers focused on at the time has to do with learning between siblings.
`Psychologists have also pointed out that the oldest child may take on a kind of mentoring role towards the younger ones. When you have to show, explain and teach others how things are done, that may also benefit you. You enter a mode where you practise communicating and structuring knowledge,´ says Salvanes.
A third explanation
The new study introduces a third possible explanation: illness.
The researchers find that younger siblings face a clearly higher risk than older siblings of being hospitalised with severe respiratory illness during their first year of life. Such early health shocks may hinder development, set them back compared with their peers, and contribute to lower earnings later in life.
It touches on something that a great many people care about.
Kjell G. Salvanes
Salvanes finds the new explanation both interesting and plausible. He points out that it may not necessarily be the illness itself that matters most, but the timing.
`It could be the point at which the illness occurs, and perhaps how often they fall ill very early in life, that makes the difference,´ he says.
In the new study, the researchers suggest that illness may explain around half of the difference between first- and second-born children, while the rest may be linked to the fact that first-borns receive more attention from their parents.
Salvanes is not surprised that the topic attracts interest.
`We are curious about how siblings can turn out so differently, and what parents do with the first, second, third and fourth child. It touches on something that a great many people care about,´ he concludes.