It's so hard not to compare your kid to other kids. Are they reading at the same level as the kids in their class? Can they throw the ball as far or as fast as the other kids on the team? Are they hitting all of the right milestones at all of the right times?

The effect is even more pronounced when those kids are under one roof.

How can you have grown out of those jeans when your brother was still wearing them at your age?

Ask your sister for help, she's the math wiz in the family. 

Why can't you make the honor roll like your brother can?

We know as parents that labels and comparisons tend to become self-fulfilling prophecies when it comes to our kids. But a new study has confirmed that the effects of our parental comparisons are even greater than one may have thought — especially when it comes to academics. A parent's belief about their child's ability in school can influence how that child performs in school. If you believe one of your kids is smart, they will likely get better grades. If you believe that another child is less capable, their grades will soon confirm the label. Ready for the sucker punch? This happens time and time again, even when the siblings' initial academic progress is the same.

In other words, the parents’ belief about the academic differences between their children wasn’t based on past grades, but the future grades of those same kids were influenced by their parents’ beliefs.

The study, which was published in the Journal of Family Psychology, looked at 388 teenage first- and second-born siblings and their parents from 17 school districts. The premise of the study was simple: Researchers asked parents which child they thought was smarter. More often than not, the parents claimed that their firstborn performed better in school. But on average, the two siblings had a similar academic record. One exception to this rule was when the firstborn was a boy and the younger sibling a girl. In those cases, the majority of parents believed that the sister was smarter.

What's even more distressing is that over time, the child who the parents believed was smarter, did eventually start to do better in school. While the grades of the child that they believed was not as smart started to plummet. The effect was small at first, resulting in a GPA difference of around 0.21. But over time, the effect was amplified, and even began to influence the paths the kids took in life.

So which came first? It's entirely possible that when the parents were asked which child was smarter, they were basing their answers not just on their child's current academic record, but on years of observations with things like goal-setting, organization, reading skills, et cetera. Statistically, firstborn kids tend to hit milestones like reading and writing before their younger siblings. Lots of theories abound on the reasons for this, but as any parent of multiple kids can tell you, there is just more time — and more pressure — to help that first kid reach those milestones. So are those firstborns really any smarter than their younger siblings, or have their parents just decided that they are based on preconceived notions?

It's pretty complicated to sort out. But it goes back to the dangers of comparisons and labeling. When a child is told (or overhears) that he is not as smart as his sibling — you can bet that even if the grades don't reflect it now, they will soon enough. Your best bet is to avoid comparisons whenever possible and focus instead on your child's strengths and abilities. Then, like everything else involved in raising kids, just cross your fingers and hope for the very best. 

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