I found this paper by Nicolleti & Rabe via @DylanWilliam. In this discussion paper the authors show evidence that when older siblings achieve more, younger siblings do very slightly better too.The interesting part: this is especially the case in poorer households. The researchers have corrected their findings for school, background,… but it’s a very difficult thing to do. Siblings often go to the same school, have the same parents,… The researchers sum up possible other factors that may have an influence on their results but that they can’t correct their findings for, still they argue (based on literature on these other factors) that their findings are robust.
The non-technical summary:
In this paper we estimate how much a younger sibling’s school achievement is affected by his/her older sibling’s achievement at school (“sibling spillover effect”). This is an important question to answer as it helps us understand whether investments in children may have multiplier effects through their impact on younger children. We are the first to investigate this issue.
The older sibling’s achievement may have a direct effect on the younger sibling’s school grades if 1) the older sibling teaches the younger sibling or helps with homework; 2) the younger sibling imitates the older sibling, for example in their work style, or conversely tries to be different, for example to avoid competition; 3) the older sibling passes on important information about educational choices or school and teachers to the younger sibling.
When trying to assess the extent of any sibling spillover effects we need to be careful that we distinguish the direct influence of the older to the younger sibling from any similarities in their exam grades that are caused by the fact that they come from the same family and are likely to go to the same school. This paper does this by combining several techniques known to economists.
Our study shows that there is a small direct effect from the older sibling’s test scores to the younger sibling’s exam marks. More precisely, for each GCSE exam grade improvement of the older sibling – for example from a B to an A – the younger sibling’s exam marks would go up by just 4% of a grade. This effect is about equivalent to the impact of increasing yearly spending per pupil in the younger sibling’s school by £670.
We find that the spillover effect is larger for siblings in families eligible for free school meals, living in deprived neighbourhoods and speaking a language other than English at home. 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/teachers. Information on this is likely harder to come by in poorer families, and the benefit to younger children therefore high. Our results indicate that siblings can play an important role in conveying education-related information in families where parents have less access to such information.
This suggests that investments into children from deprived families can have considerable multiplier effects on younger siblings.
Abstract of the paper:
We provide the first empirical evidence on direct sibling spillover effects in school achievement using English administrative data. Our identification strategy exploits the variation in school test scores across three subjects observed at age 11 and 16 and the variation in the composition of school mates between siblings. These two sources of variation have been separately used to identify school peer effects, but never in combination. By combining them we are able to identify a sibling spillover effect that is net of unobserved child, family and school characteristics shared by siblings. We find a modest spillover effect from the older sibling to the younger but not vice versa. This effect is considerably higher for siblings from deprived backgrounds, where sibling sharing of school knowledge might compensate for the lack of parental information.