A discussion paper published by the Institute for the Study of Labor (IZA), Germany, has linked older children with an improvement in the grades of their younger siblings.
The researchers looked at information from the UK’s National Pupil Database, and examined GCSE results between 2007 and 2010, which provides data on 220,000 siblings. The researchers controlled for any effects that might be caused by the children being from the same family or going to the same school. They found that an increase in the test scores of an older sibling of one standard deviation led to an increase in the corresponding test score of the younger sibling of 2.4% of a standard deviation. For each exam grade improvement of the older sibling – for example from grade B to A – the younger sibling's exam marks increased by 4% on average.
The effects doubled when children attended the same school. For families on low incomes, living in impoverished neighbourhoods, or where English is not spoken at home, the effect was even higher – 6-8% of a standard deviation increase in test scores of the older sibling.
The authors suggest that older siblings may play an important role in providing education-related information, particularly in families where parents have less access to this information.
Source:Sibling Spillover Effects in School Achievement (2014), IZA