Why Do Girls Do Better At School?

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In most developed countries, girls do better than boys at school. There’s a ton of evidence for this - see here, here, or here. This hasn’t always been the case - girls’ grades have been getting a lot better over time. Even in subjects where boys are often thought of as performing better than girls (like maths), I think the evidence generally suggests that girls actually outperform boys at school, but the effect size is smaller than for other subjects. That’s the finding from Voyer and Voyer’s meta-analysis, in which they note that:

“A small but significant female advantage (mean d = 0.225, 95% CI [0.201, 0.249]) was demonstrated for the overall sample of effect sizes. Noteworthy findings were that the female advantage was largest for language courses (mean d = 0.374, 95% CI [0.316, 0.432]) and smallest for math courses (mean d = 0.069, 95% CI [0.014, 0.124]).”

It’s true that there are some studies that suggest that boys do better in maths, but they seem to be outnumbered by those giving girls a small advantage. Either way, it’s pretty clear that girls do better than boys at most subjects, even if the difference in maths is debatable. But why do they do better?

The most obvious suggestion is that girls are just smarter than boys. I think we have pretty good evidence that this isn’t the case - girls don’t score better in IQ tests than boys. That isn’t to say that there aren’t any differences between how boys and girls do on IQ tests - a few studies have found that boys show greater variability in IQ (they’re overrepresented among people with very high intelligence and with very low intelligence). There’s also some evidence that girls have a small advantage in verbal intelligence and that boys have a small advantage in numerical ability, but the mean IQ of boys and girls does seem to be about equal, so it seems unlikely that this explains why girls do better at school.

The most interesting paper I’ve found exploring the reasons for the gap is Spinath et al. (2014). They look at every personality trait that is correlated with educational attainment, and check which ones are also correlated with gender. The method here is to use mediation analyses - we’re looking at whether the correlation between gender and educational attainment disappears or is diminished when you control for certain variables. For instance, if it were the case that the correlation between being a girl and doing well at school disappeared when you controlled for trait conscientiousness, we might conclude that the reason that girls do better at school is that they’re more conscientious. This helps us with an obvious problem with just looking at personality traits that are correlated with both educational attainment and gender: if it’s the case that gender and educational attainment are correlated, we would expect most personality traits correlated with gender to be correlated with educational attainment.

Okay, so what do they find? Well, they look at one study that shows that when you control for self-discipline (which seems pretty similar to trait conscientiousness, although more similar to the ‘industriousness’ component of conscientiousness rather than the ‘orderliness’ component), the association between gender and educational attainment shrinks to non-significance. So, self-discipline seems like it’s pretty important here. And that holds after controlling for intelligence and other potential confounders. But self-discipline still seems to only explain about 50% of the association between gender and educational attainment.

The other interesting thing is that it seems like agreeableness might explain some of the association. Although we know that agreeableness is often negatively correlated with income (and there have been claims that this explains some of the gender wage gap), it’s positively correlated with how well you do at school. This isn’t totally surprising - being agreeable at your job might make you less likely to negotiate for a pay increase, but being agreeable at school might make you more likely to get on well with teachers and learn more in class. And the evidence seems to fit with this - one study (as summarised in Spinath et al.) found that trait Agreeableness explained 25% of the association between gender and educational success. 

But why do girls have more self-discipline in the classroom? The evidence for women being higher than trait conscientiousness than men in general isn’t very good. While there is a pretty clear gender difference in Agreeableness and Neuroticism (women are higher in both), the findings of conscientiousness are inconsistent. There is some evidence that women are higher in the self-discipline aspect of trait conscientiousness (as well as the dutifulness aspect), but this seems inconsistent across cultures and not the case in all the literature. But girls seem like they really are more disciplined at school in most countries in the developed world, and that discipline leads to them getting better grades. So, what’s the explanation here?

Well, there’s some good news and some bad news! I’ll start with the bad news: I’m not really sure why. But here’s the good news: there are some really interesting studies that might let us get closer to the answer. Or they might not - but I’m going to write about them anyway because they’re fun to read. One of the most interesting papers I’ve found, Mittelman (2022), has a weird finding. In the United States, gay men have extremely high levels of educational attainment. If gay men in the US were their own country, they would have by far the highest college completion rate in the world. Lesbian women also do pretty well, although one odd thing is that their grades at school haven’t been getting any better - while girls as a whole have been doing better and better at school, this is confined to straight girls. So, lesbian women had a sizeable advantage over straight women, but this advantage has diminished over time. In fact, the number of lesbian women getting bachelors degrees seems to actually be decreasing slightly. 

I guess one thing that might come into play here is that LGBT kids at school might be less focused on romantic relationships (especially if they’re in the closet), and so gay boys at school might have less of a problem staying disciplined? Another explanation that seems plausible to me is that LGBT people who are willing to say they’re LGBT in a survey might be more likely to be from more socially liberal (and richer, more successful) backgrounds, so there might be a selection effect here. The ‘romantic distraction’ hypothesis seems to have some support: Gibb et al. (2008) found that there was a significant achievement gap between boys and girls at coeducational schools in New Zealand, whereas at single-sex schools there was a non-significant gap in favour of boys. So, could it be the case that girls do better at school largely because they’re more focused on work, and they’re more focused on work because they don’t find their male schoolmates much of a distraction, whereas boys struggle to get schoolwork done when surrounded by girls? I think it fits with a lot of the evidence. Gay men also apparently tend to be more agreeable than straight men, so that could explain why they do so well, given that trait agreeableness seems to lead to educational success. 

What do you think? I’ve probably missed quite a lot of obvious stuff - leave a comment or reach out to me on Twitter if you think there are some other interesting explanations. I’ve barely scratched the surface of the literature here so I’m sure there’s a ton of cool stuff that I missed, let me know if there’s a study you’ve seen that I might find interesting.