The stereotype of the oldest sibling is that of a Type-A overachiever, high-strung and highly successful. The effect of birth order on personality and achievement is something that seems like common knowledge, and there is research to suggest that firstborns have the advantage. But it’s less set in stone than it seems, partly because many studies compared siblings from many families. “Birth order is clearly a within-family phenomenon,” points out a study published by Feifei Bu of the University of Essex as part of the Institute for Social and Economic Research’s Working Paper Series.
Her study takes data on 3,552 people organized into 1,503 clusters of siblings from the British Household Panel Survey (and its successor, the UK Household Longitudinal Study) and looks at how birth order relates to educational aspiration and achievement, both across and within families.
To measure educational aspiration, Bu looked at children’s responses to this question at age 13: “Do you want to leave school when you are 16, or do you plan to go on to sixth form or college?” Future waves of the longitudinal surveys followed up with these children to see the highest level of education they achieved. (Some of the research subjects aren’t yet old enough to have completed college degrees, so she measures instead whether they “gained any qualifications following the end of compulsory schooling.”)
As you might predict, firstborns had greater educational aspirations than their younger siblings—typically they were about 7 percent more likely to want to stay in school. Firstborns were also about 16 percent more likely to gain higher educational qualifications. (However, the spacing of the siblings did seem to have a buffering effect here—“the wider the age gap is, the more likely that individual attains further education,” the study reads.) The firstborn advantage was significant both within families and across families.
There are gender differences at play, as well. Girls were 13 percent more likely to aspire to higher education than boys, and 4 percent more likely to actually achieve those qualifications. Though this seems to suggest that firstborn girls would be the pinnacle of success, outpacing even firstborn boys, the study says it found “no evidence that… the birth order effect differs between females and males.” To be predisposed for success then, best to be the oldest sibling, but if not, better to be a girl.