"school uniforms increase/reduce crime"
While school uniforms may reduce some kind of peer pressure, they increase other types of peer pressure between students.
Some suggest that school uniforms reduced discrimination, bullying, violence and crime, but there is little or no evidence in research to support that. Anyway, these are different arguments that are discussed in more detail elsewhere at this site.
School uniforms may impose some sense of equality upon students, but whether this was desirable is a matter of politics. It's inappropriate for a public school to impose one specific political view, while silencing the opposite view.
Mandatory school uniforms at public schools are prone to violate inalienable rights, including freedom of expression and the prior right for families to decide how their children are to be educated.
"School uniforms identify outsiders." [source]
"School uniforms reduce peer pressure - as all students dress the same, there's less rivalry in clothing. School uniforms reduce bullying and they make it more difficult for students to carry weapons on them." - anonymous
"There have been several incidents of NONstudents entering schools and raping and/or beating students while dressed similarly to students. You want to keep "outsiders" out? Lock the doors, make a policy that has students wear easily seen ID tags and have vigilant staff." [source]
"Does everyone who enters the schoolgrounds wear uniforms? Do all the parents and brothers and sisters who come and pick up their children and who come and speak to the teacher after school wear uniforms? Do all the people working on the grounds, the gardeners, the maintenance workers wear uniforms? Do all teachers, principals and administratibe staff wear uniforms? So many people don't wear uniforms, yet nobody made a security point out of that." [source]
"The uniform makes the student an easily identifiable and predictable target walking down the same road every day at the same time." [source]
"Uniforms set students of one school up against students of another school, making them violent towards those wearing another uniform. School uniforms encourage gang behavior with all associated problems of security, safety, bullying and the negative mentality, setting up kids towards their own parents, etc." [source]
"Uniforms encourage this kind of gang behavior. Uniformity in clothing and gang behavior go hand in hand; what is sacred for most gangs is their patches and their colors and stripes; ridicule them and the gang will respond violently. Schools that put their students into uniforms glorify that kind of mentality. You can see that kind of violence occur between people from different neighborhoods. Normally, they act friendly towards each other, but if there is a sport event in which the two neighborhoods are facing each other, they suddenly dress in their colors and become violent. Violence and uniforms go hand in hand, not just in wars, but also in "peaceful" confrontations such as sport. Uniforms are inherently confrontational, they are symbols of violence! Furthermore, the fact that they did wear uniforms made the kids believe they were less easily identifiable individually. If attackers are identified, the clothes they wear play a major role in tracing back to what extent each individual participated. If they're all in uniform, that become a lot more difficult - the culprits know this and act accordingly." [source]
"Uniforms encourage gang behavior, with all the associated security problems. Uniforms give students the impression that violence and theft were condoned if directed towards those who don't wear (the same) uniforms. Crime is very much a mentality-issue, which should be approached by stimulating students' development of character and personality, not by suppressing this." [source]
"What if your child was abducted? What's one of the first things the police ask you? A description of what your child is wearing. The poor community doesn't have the extra clothing for their children so they have to wear their polos before and after school and on weekends. This doesn't *level* the playing field... it exacerbates the class issue. A group think~heard mentality and definitely a - do as i say not as i do ideology." [source]
"What if your child is missing? You can call the police, you can call each of the local shops to see if your child has been spotted, as long as you can tell them what clothes your child is wearing. You can tell your friends to go out looking, driving around in cars, etc. But, if it's a school uniform, that won't be much help." [source]
"Another safety argument is that school children could be more easily identified while on excursions. But does this really increase safety? Uniforms make it easier for teachers to check if all children are still there, i.e. by counting the number of kids. But uniforms also make it easier for people with bad intentions to spot and target children who are at risk of losing contact with the group. Whatever way one looks at it, it seems that the danger is created not so much by the absence of uniforms, but by the way school operates. School puts thirty-odd children together in the care of one teacher. Look at the hundreds of cars circling around the school twice a day, trying to find parking places. Apart from the risk of traffic accidents, this havoc makes it easy for someone with bad intentions to follow a child and drag this child inside a car. Even if bystanders notice screaming, they may think it is a case of a parent disciplining an obstinate child. The uniform identifies the child walking down the road as a target who is alone, on the way home, unaccompanied. Children without a uniform seem less at risk, as they are likely to be brothers or sisters who are picking up a uniformed student." [source]
"School uniforms give students just another reason to bully each other, e.g. with comments such as: "pull up your socks" or "tuck in your shirt" or "tidy up your tie". Your assumption that uniforms lead to less peer pressure is not supported by studies into such questions." [source]
"Uniforms have another tradition - they can be used to distinguish friends from the enemy (i.e. those wearing the same, respectively a different uniform). The obvious example is soldiers from different sides wearing different uniforms. Note that the uniform not only serves to prevent friendly fire, there is an even more sinister purpose - uniforms make it hard for soldiers to desert, run away or change sides. Those who do defect, typically face the death penalty, an even harsher fate than preserved for enemy soldiers, who are merely taken prisoner, held captive and who are exchanged, or set free after the hostilities are over. The uniform acts as a strait-jacket, meant to mould the person who wears it and meant to kill any 'free' spirit that dares to speak out against oppression. This can result in schools openly condoning bullying against students who dislike uniforms. In fact, the sheer use of uniforms in schools is unacceptable, not merely because it constitues a suppression of individuality, but because it seeks to victimise anyone who doesn't comply, as becomes evident in the frequent parading, uniform checks and inspections, etc." [source]
"Uniforms are inherently confrontational, moreover, they are symbols of violence! Sport clubs and street gangs use colors to set up people from one area against people from another area. This can lead to violence between people from different neighborhoods, typically coinciding with sport events that put teams of one area against the other. Normally, people will act friendly towards each other, but if there is a sport event in which the two neighborhoods are facing each other, they suddenly dress in their colors and become violent.
Thus, violence and uniforms go hand in hand, not just in the sense of physical violence as in wars, but also in "peaceful" confrontations such as sport, and as becomes manifest in the master-slave relationship that uniforms invoke. Furthermore, uniforms make the wearer prone to hide behind a group. Dressed up in uniforms, kids all wear the same clothes, which makes them believe they were less easily identifiable individually. Normally, if the culprits of attacks are identified, the clothes they wear play a major role in tracing back to what extent each individual participated. If they're all in uniform, that become a lot more difficult - the culprits know this and act accordingly.
In the US, uniforms emphasize ethnic differences, because they prevent students from choosing clothes that would take away the attention from ethnic features such as the color of their skin. In the absence of the class differences of the UK and the patriotic use of uniforms in continental Europe, uniformity in clothing in the US goes hand in hand with gang behavior, specifically ethnic gangs; what is sacred for most gangs is their patches and their colors and stripes; ridicule them and the gang will respond violently. Schools that put their students into uniforms glorify that kind of mentality." [source]