AAGAL. That won’t mean anything to you. But 25 years on, I still know what it stands for: Almost As Good As Leila (Leila being my older sister). “AAGAL” was a comment my maths teacher used to scrawl on my work.

There are downsides to having a smart sister ahead of you in school - but there are pluses, too. Before I joined Year 7, Leila taught me how to say, “I have a rabbit called Prince” in French and German. She also told me to wear my tie the “skinny” way around because a “kipper” was social suicide.

But the thing that really stuck with me was AAGAL. The fact that I remember all this tells us two important things about sibling relationships at school: that they have the power to shape a pupil’s school experience and that the way teachers respond to those relationships can have a lasting impact.

Exactly what the sibling effect might be, though, and how the actions of teachers play into it, is hard to say, not least because there’s limited research into the impact that siblings have on each other’s experience of and attainment in school.

This is something that Katherine Davies, senior lecturer in sociology at the University of Sheffield, thinks needs to change.

“In sociology and the sociology of education, there’s been a real focus on the importance of parents and a research interest in friends. But the sibling relationship has been really overlooked and I think that’s a mistake,” she argues. “There are some really specific things about the sibling relationship that make its influence on education unique.”

In her research, Davies talks about how the sibling relationship is “sticky” - love them or hate them, siblings are usually a part of both a student’s home and school life (unlike friends and parents) and are therefore a difficult influence to shake. With multiples (such as twins), that stickiness is likely even stronger.

So, what do teachers need to know about this effect? Davies identifies three key ways that siblings can affect each other in school.

First, resemblances between siblings mean that their reputations can rub off on each other, especially if they’re in the same school. Second, there are normative ideas about how siblings should support one another based on age and gender - think of the classic archetype of the protective older brother.

Finally, as a young sibling watches their older sibling progress through the school system, they can use them as a yardstick against which to measure their own experiences and achievements.

Not only can all this influence a young person’s enjoyment of school, but it may also impact their outcomes. Cheti Nicoletti, professor of economics at the University of York, conducted research in which she found that, with siblings of different ages, an increase of one grade in the older student’s GCSE exam result led to a 10 per cent increase in their younger sibling’s corresponding grade, even if they didn’t go to the same school.

“This is quite significant. It’s equivalent to increasing yearly per-pupil school expenditure in the younger sibling’s school by around £1,000,” she explains.

“It’s difficult to determine exactly what causes this effect,” she continues, “but our research suggests it’s likely some combination of the older sibling helping, through teaching and support with homework; modelling academic behaviours, educational aspirations and values; and sharing information about how the school system works.”

Brothers and sisters in schools: the sibling effect

In other words, having an older sibling could give you an educational advantage. And Davies notes that there may be further benefits in terms of children being better able to integrate into school culture.

In her research, she conducted interviews with more than 100 young people and found that “there was definitely a sense that a younger sibling might get a bit of help with the culture of school. Some of that you can soak up from your siblings, even if they haven’t actively talked to you about it, especially if you live in the same house.”

This transfer of cultural information might be especially significant in families where English is not the first language, Nicoletti points out, where parents may not be able to provide as much support in sussing out the school system. Her research found that the sibling “spillover effect” is larger in these families, suggesting that “the older sibling provides a lot of useful information to the younger child”.

What’s more, it seems that this overspill of information from sibling to sibling can have a lasting impact.

“That day-to-day soaking in, watching your older sibling, can help you orientate yourself in the education system - you have an idea of what it’s going to be like studying for GCSEs or what going to college might be like. You get a long view of the journey through education,” Davies explains.

Indeed, in Nicoletti’s research, role modelling seemed to play a part in why an improvement in an older sibling’s grades had a knock-on effect for the younger sibling: “If you see your older sister sitting at the desk doing her homework, for example, you might then go and do yours. It’s a case of imitation,” she says.

Yet there is a downside to the spillover effect, too. Nicoletti’s research has found that the effect holds true (although to a lesser extent) when the older sibling’s performance is poor. That is, if an older sibling’s grade drops so, too, does the younger sibling’s.

Even more worryingly, she found this plays into widening the inequality gap. “In families eligible for free school meals, children are much more likely to have poor test scores, which means it’s much more likely that the spillover on to siblings is a bad effect,” she explains.

And just as information about how to fit in at school can be passed from sibling to sibling, so, too, can negative perceptions, suggests Charlotte Beardsley, a sociology teacher at Saint Benedict School in Derby.

“If they didn’t have a good experience, the older sibling’s experience can cloud the younger sibling’s judgement of a subject or teacher,” she explains.

This negative transfer is obviously something that schools would wish to avoid. But navigating the complexity of sibling relationships in order to do that is no easy feat because every relationship is different, says Amy Forrester, director of pastoral care (key stage 4) and head of Year 10 at Cockermouth School in Cumbria.

In her experience, she says, students bring up the influence of their siblings relatively regularly - especially the idea of being compared to older siblings in the same school - but they don’t all respond to this influence in the same way.

“You’ve got ones where it affects them really positively and others where it can have quite a negative impact,” she explains. “Say, for example, the older sibling has not had an easy time in school or their behaviour has been particularly challenging, often the younger sibling can feel as though they’re tarred with the same brush - that they’re expected to be like their older sibling when, obviously, they’re not. They’re a totally different human being.”

Beardsley says that she has often heard the same thing. In fact, she has encountered students who go as far as to deny they’re related to their sibling when asked.

On the flip side, Forrester says: “Sometimes a student’s belief that they’re being compared in a negative light to their sibling can actually motivate them to prove they’re different.”

Davies has found a similar variety of experience in her conversations with young people, she explains, with many talking about how you either live up or live down to your sibling’s reputation.

“Both those things can be challenging. Some young people feel under pressure to be as good as their sibling or good at the same things,” she says.

And these effects seem to come into play whether siblings attend the same school or not, she continues.

“I had some young people in my study who went to different schools and their siblings still affected them. One pair of sisters springs to mind. The younger sister went to a different school to the elder and wasn’t settling in well. She had this whole narrative of ‘my older sister was fine by Year 8 - what’s wrong with me?’

“Even though they were at different schools, the way she made sense of her experience was through her sister’s.”

On top of all of this complexity, Davies adds, there are yet more challenges for young people to navigate, which stem from societal expectations of how siblings should interact.

For example, there’s the stereotype that older brothers will always stick up for younger ones, while older sisters will give the lowdown on how to wear make-up the “right” way.

However, she notes: “There might be a sense of obligation among older siblings to help younger ones but that doesn’t always mean that, in practice, it happens. Sibling relationships can be more complicated than that.

“There are a lot of contradictory tropes about siblings. On the one hand, you get this idea of this close sibling bond, like in [the film] Frozen. But then there are also ideas about sibling rivalry - look at all the stuff about Princes William and Harry.

“The sibling relationship is often seen as imbued with lots of emotion - whether that’s arguments, rivalry, closeness, being best friends - so there’s no one stereotype that always sticks.”

It’s a lot for young people to manage and this is one of the reasons why Davies believes that a lot more research is needed in this area.

Until that research materialises, however, what can schools do to make sure that they are not playing into sibling stereotypes in a way that might be harmful? How can teachers maximise the benefits and minimise the challenges of how sibling relationships play out in schools?

Forrester believes that the golden rule is for teachers to completely avoid outright comparisons of siblings - even if those comparisons are well intentioned.

“If a student says, ‘Do you know my brother?’ for example, I always say ‘no’, even if the answer is ‘yes’, because I don’t want them to think I’m biased,” she says.

Beardsley applies the same tactic: “I make that conscious effort to say, ‘I don’t care who your brother or sister is or what you did last year. This is a new lesson, a new year, a fresh start’.”

Doubly important

Avoiding direct comparisons may be particularly important when it comes to twins, suggests Carla Parkinson, family support officer at Twins Trust.

“We always say to teachers and parents, never to compare a twin to a twin. Compare them to their peers in class or nationally,” she says. “Don’t label them ‘the twins’ or use stereotypes like ‘the clever one’ or ‘the cheeky one’. Their sibling shouldn’t be the benchmark they’re measured against.”

On the subject of twins, what about class groupings? Is it better for schools to place twins together or apart?

“There is no conclusive research on whether twins and multiples are better off together or apart, so there should be no blanket policies in schools. Dynamics vary hugely - they’re individuals,” says Parkinson.

The decision about how to group siblings needs serious thought as well as input from parents and teachers, she adds. And when it comes to events such as parents’ evenings, it is also important for schools to treat twins as individuals.

“Some primary schools club twins together. In fact, each student should have their own slot with, ideally, an extra five minutes to talk about their twinship and if it’s impacting them,” suggests Parkinson.

Always striving to treat young people as individuals, regardless of who their siblings are, seems to be a useful rule of thumb, not just for those who have a twin but for any pupil. This is something that most schools would already say they do, although how far that is actually happening in reality is a different matter.

However, at the same time as treating students as individuals in their own right, teachers should also not completely ignore the influence that siblings have on one another, says Davies - and that means they have a fine line to walk.

The most helpful thing teachers can do, she suggests, is to get to know the dynamic of specific siblings.

“If a pupil gets injured, for example, should you get their sibling to sit with them while they wait for their parents? You make a decision based on what you know about those children, not assumptions about how sibling relationships work,” she says.

For some, having their older brother or sister called could, quite literally, add insult to injury.

And when thinking of siblings’ influence on each other, it is easy to assume it always runs from older to younger, but can it go in reverse?

“In my research, there were reports of older siblings getting help from their younger siblings, but it doesn’t happen as much at this point in life because school is very much ordered around age,” says Davies.

However, she notes that context is key here: “I did some research in a club where children went in the school holidays and they stuck together way more than they would in school. It was an unfamiliar place and older siblings were really grateful for their younger siblings - they were a source of support for one another.”

Beardsley notes that even in school, younger siblings may still have an influence in an indirect way: “I think if there’s an older student who’s not had a good time at school, and then they see their younger one coming up and thriving, that could make them feel a bit resentful or perhaps a bit regretful that they didn’t try harder.”

The last thing they need? A load of comparisons heaped on top.

Role model potential

With all this in mind, Nicoletti notes that there are two other things that sibling research suggests are really important for schools to consider: role models and information.

Schools need to ensure that there is no “inequality in information”, she says - that means recognising that pupils without an older sibling (particularly those from families that do not have English as a first language) may need extra support with getting all the correct information on things like how to prepare for exams.

And it can be very useful to tap into the role model potential of siblings, to “give the right motivation to all children”, she adds. This can be done through mentoring schemes to offer the same support to every child, whether they have an older sibling or not.

“For students from family backgrounds where they would be the first generation to go to university, it would be especially important to have a pseudo older brother or sister to guide them,” Nicoletti explains.

Forrester says that, at her school - pre-Covid - they had a buddy system, whereby sixth-formers would run lunch clubs and check in with the younger students.

Schemes like this one mean all pupils, regardless of their sibling status, can reap some of the benefits that come with having a supportive older sibling in the years above - with the added bonus of not having to suffer the negative consequences that, all too often, come as part of the brother or sister package.

Jessica Powell is a freelance journalist

This article originally appeared in the 9 July 2021 issue under the headline “Not my sibling’s keeper”