Study Shows School Uniforms Improve Attendance, But Not Grades


The school uniform debate isn’t exactly raging these days, but there’s still data to be gathered and examined as to how slacks and blazers affect school kids. According to a new study by researchers at the University of Houston, school uniforms seem to be decently effective at improving student attendance and teacher retention, but have no real impact on improving student achievement. For their data, researchers looked at the effects school uniforms had on a large urban school district in the Southwest United States.
Here’s the abstract:

Uniform use in public schools is rising, but we know little about how they affect students. Using a unique dataset from a large urban school district in the southwest United States, we assess how uniforms affect behavior, achievement and other outcomes. Each school in the district determines adoption independently, providing variation over schools and time. By including student and school fixed-effects we find evidence that uniform adoption improves attendance in secondary grades, while in elementary schools they generate large increases in teacher retention.

They further find that:

[U]niforms have a positive influence on student attendance in secondary grades. Attendance rates in grades 6 through 12 increase by 0.3 to 0.4 percentage points after a school adopts uniforms. On the other hand, we find little evidence that uniforms have lasting impacts on achievement, grade retention, or the likelihood of students switching schools or leaving the district for all genders and grade levels.

Joshua Northey

.3 to .4 % is a pretty small benefit.

I wonder how this would compare to making students carry a school sponsored bag every day, or other mundane task.

I might guess the benefit might be entirely created by losing 1 or 2 students who simply won't go to a school that has uniforms and transfer. It doesn't take discouraging many bad apples to make a .35% change in attendance.


The kinds of parents who allow their kids to decide when and where they go to school based on the uniform policy aren't likely to care whether the kids go to school or not.


My guess is that the temptation for students to cut is less once they realize they'll be stuck out all day wearing their dorky school uniform.


Doesn't this study also imply the corollary that *attendance* does not "have lasting impacts on achievement... for all genders and grade levels."?

Pablo Martínez-Almeida

I have not read the study but my first thought was similar. A possible takeaway could be that small increases in attendance (due to uniforms) do not impact grades significantly.

However, if the level of attendance is low enough small increases might make a bigger difference in grades. I don't know if that is covered in the study.

More thoughts:
- The study says "On the other hand, we find little evidence that uniforms have LASTING impacts on achievement...". Does this mean that there is a temporary impact on achievement?
- What about differences between good and bad students?


Are grades the correct metric? I teach, and at the end of each term, I adjust my average to 83-85. Seldom do they change for any reason.


The reason many public schools are making students wear uniforms is not to boost achievement, it's to reduce gang-related disputes. As anybody who has worked at an urban public school can tell you, clothing in gang-related colors causes a huge amount of disruption and often leads to violence.


This is exactly what I was going to post. The uniforms eliminate obvious gang oriented distractions and the policy is designed to bring more unity to a student body, build self confidence and discipline in students, and diminish various social and economic differences between students.

" uniforms seem to be decently effective at improving student attendance and teacher retention, but have no real impact on improving student achievement." Are there not data to show that improved attendance and retention of educators are themselves catalysts to improved achievement?

Steve S.

I think there is a bit of reverse causality at play here. Perhaps instilling a uniform policy - an idea that is conservative in nature - increases teacher retention because there are other similar conservative policies being enacted at the school at the same time. As for what I consider teacher supportive/conservative policies: holding students and parents accountable for both large and minor things, holding high goals and standards of achievement for all students, etc.


.3 to .4 % is what, .72 more of a school day a year. Even if it was significant the effect size has to be so small. Also if wearing the unis did increase attendance then these guys are saying that attendance is not related to achievement. One would think that attendance would mediate the relationship between wearing the uni & achievement.


Uniforms make the kid cutting class more obviously belong in school, so I can see that they might increase attendance in secondary school, particularly for the most at-risk, such as older teens who might pass as adults.

But increase teacher retention at elementary? I suspect that's not a result of the uniforms, but more likely that introducing uniforms is an active step taken by a group interested in improving the school. Therefore, they tend to be introduced in schools that are actively managed and actively trying to improve and rarely introduced at incompetently managed schools. The quality of school management, not the presence of uniforms is what drives teacher retention.

I'd also assume that the schools with students whose parents really don't give a damn, might not dare introduce uniforms for fear not enough parents would actually buy them for their kids.

My bet is uniforms are an indicator of drivers of teacher retention, not a cause.


Caleb b

I went to a school with voluntary uniforms in 8th grade. I liked it bc I was poor and could just wear the plain uniform everyday to cover the fact that I couldn't afford designer clothes. It probably didn't affect my grades bc I was always a good student, but it certainly helped me to feel better as I didn't have the anxiety of my crappy 2nd hand clothes weighing me down.


How can it be called a uniform if it isn't mandatory? Wouldn't that just be wearing semi-formal clothes to school? Pretty sure every school that doesn't have a mandatory uniform lets you do that.

caleb b

If the school didn’t have the optional uniform policy and I wore uniform type clothing, I would have been ridiculed to no end.

Uniforms were encouraged but not mandatory. There were various incentives for wearing a uniform, like leaving for lunch five minutes early, or getting a chance to step in the "money machine" for 1 minute. Because of the incentives, it became socially acceptable to wear a uniform.

The Money Machine was a large box with $1 bills in it. For 1 minute, the person in the box tried to catch bills and slide them through a slot on the side. A leaf blower was attached to the bottom corner, making it more difficult. The max any kid got all year was $12, and most left with around $5. Total, there might have been only about $200 in there. It did wonders for uniform wear. Not only did you get the money, but it was during lunch and the whole lunch room watched as you tried. The attention alone was enough to incentivize some.

It might not work everywhere, but it worked well at my school. Again, it likely had zero affect on my grades, but it did help my comfort level. Maybe that meant I didn't get into any fights, or maybe that I didn't disrupt class, or maybe it made a school wear kids didn't make fun of other kids based on clothes. Regardless, I was grateful for the policy.


A Nother

The study doesn't show that attendance has no influence on achievement,

A Nother

Assuming the consistent identity of the students who showed up more often when uniforms were required, which may or may not be accurate, the study shows, at most, that these students' attendance had little impact on their performance. Is this surprising? Would you expect the low-achieving truant suddenly to catch up with the average-achieving student who attends more consistently, or the formerly absent student who gets A's and B's to improve his or her GPA when there isn't much room for improvement?

If the improvement in attendance was realized by a single group of otherwise absent students, then perhaps the study confirms my instinct that these students' performance was set before the uniform policy was imposed. It says nothing about whether the high-achieving students would have performed as well if they suddenly stopped attending. It doesn't say that students generally don't benefit by attending classes.


Barbara Sterling

I thought the reason for uniforms was to stop the kids from wearing gang attire, which causes fights and intimidation of other students, giving all students a safer environment. This issue was not addressed.

John Patton

What does it say that "greater attendance" as a result in the uniforms apparently doesn't have a positive effect on grades?


This has nothing to do with economics, it's social psychology. But since Altucher didn't write it, it's cool.


I had to wear a uniform from the ages of 12-18. For the first few of those years I'm glad we had it. Early adolescence was probably made a little easier since there was no peer pressure based on how we dressed when everyone had to dress the same. That might also have helped relieve social pressure on poorer families: one uniform probably being cheaper than lots of fashionable clothes.

From about 15-18 I found the uniform mildly annoying since we were past the worst peer pressure. In general I'm glad we had the uniform duing my teens.