How, precisely?
Same gibberish line is given constantly with zero proof. Uniforms do nothing for discipline, or "corps d'esprit" as has become the modern excuse for them. All they do is give something for authoritarians in the education system to have a point to prove over. Every pupil resents...
School uniforms - a tool of crap teachers to try gain control rather than respect. Hideous invention. I'd be for all state-funded schools banning the damn things as there's so many rackets going on with supply of branded items etc.