But new research has found that having an older brother or sister who does well at school boosts the performance of younger siblings too.
According to a study by academics at the University of Essex’s Institute for Social and Economic Research, having a high-achieving older sibling is equivalent to £670 of school spending on the younger sibling’s score.
The effect of what has been called “the sibling spillover effect” doubles if the siblings attend the same school.
The study, Sibling Spillover Effects in School Achievement by Dr Birgitta Rabe and Professor Cheti Nicoletti, used data from the National Pupil Database, which covers the results of 93 per cent of children in the UK through their time at state school.
It analysed siblings’ key stage 2 results and their GCSE scores between 2007 and 2010.
The authors believe the study will be particularly interesting to policy-makers tracking the progress of the Pupil Premium initiative – because the sibling spillover effect is even more pronounced in poorer families.
“We found that the sibling spillover effect is larger in families eligible for free school meals, living in deprived neighbourhoods and speaking a language other than English at home,” said Dr Rabe.
“This means that children from more deprived backgrounds benefit more from a high-attaining older sibling than children from more affluent backgrounds.
“It may be that the effect arises through information-sharing about educational choices and schools or teachers. Information on this is likely to be harder to come by in poorer families and the benefit to younger children therefore high.
“Investing in enhancing the progress of children from deprived families is even more worthwhile when we see there are considerable multiplier effects on their younger siblings.”
The study, Sibling Spillover Effects in School Achievement, can be accessed at http://bit.ly/1B9ZGSq