From Marcia and Jan in The Brady Bunch to Ross and Monica in Friends, sibling rivalry has long been a driving force of brothers and sisters who vie for their parents’ attention. While complaints of feeling unappreciated stem from younger siblings feeling outshone by older siblings' achievements, there may be some truth to the birth order effect in families. According to a recent study conducted at the Institute for Social and Economic Research at the University of Essex, firstborn children, specifically females, are more likely to be ambitious and successful in life due to parental investment, or nurturing from parents.

"It is interesting that we observe a distinct firstborn advantage in education, even though parents in modern society are more likely to be egalitarian in the way they treat their children," said Feifei Bu, lead researcher of the study, to The Guardian. The debate over the effects of birth order remain unresolved partly due to criticisms about the types of data and analytic methodologies used in studies that suggest character traits are based on where individuals fall within the lineup of siblings. Although the scientific community remains divided about this within-family phenomenon, Bu sought to shed light on whether firstborn children enjoy a distinct advantage over their later-born counterparts.

To investigate the effects of birth order on educational attainment, Bu followed 1,503 sibling groups and 3,532 individuals through the British Household Panel Survey and its successor, Understanding Society. The study analyzes the role of young people’s aspirations, estimating the effects of birth order on adolescent educational aspirations, and the importance of these aspirations on later achievement. The participants in the study were all siblings living in the same families.

When the participants reached the age of 16, they became members of the “adult panel,” which meant all members of sample households aged 16 or older were interviewed annually. This allowed researchers to proactively track their later educational progress. The participants' educational aspirations were measured by responses to the following question on school-leaving: “Do you want to leave school when you are 16, or do you plan to go on to sixth form or college?”

The findings revealed firstborn children were seven percent more likely to continue their education than younger siblings, even after parents’ education and professional status were accounted for. Within firstborns, girls were found to be 13 percent more ambitious than firstborn boys, and they were also four percent more likely to have further education qualifications. Overall, the probability of firstborns furthering their education was 16 percent higher than their younger siblings.

Despite the disparities on educational attainment in same family households, parents could strive to have children more likely to become high achievers if there is a gap of at least four years between each child. Therefore, the wider the age gap between siblings, the greater the likelihood of younger siblings achieving higher qualifications. "It shows us how educational disparities exist not only between families but also within families," Bu said.

The reasoning behind why the eldest are more likely to be successful in life may simply be due to parental nurturing. “It could be that the parents simply devote more time and energy to them — it could be they are actually more intelligent. For me, I tend to lean towards the theory that parental investment is possibly at work here,” Bu said, the Daily Mail reported. This finding feeds to the nature versus nurture birth order debate.

In a similar 2009 study, a team of researchers found family size and birth order affects children’s subsequent educational attainment. The finding supports the theory there is a trade-off between child quantity and “quality” and that siblings are unlikely to receive equal shares of parental resources or parental investment when it comes to children’s education. Overall, the study suggests parental investment is decreasing within birth order.

The truth of birth order effects will unravel over time as children are changing as they grow older, and accessibility to educational resources is evolving.


Bu F. Sibling configurations, educational aspiration and attainment. Institute for Social and Economics Research. 2014.

Booth AL, Kee HJ. Birth order matters: the effect of family size and birth order on educational attainment. Journal of Population Economics. 2009.