Do uniforms improve performance?

Well, we could not find the exact answer to this question. That's because there are many researches about it and many results come up.
 YES... In 2007, researchers found out that only one of the top-performing 100 state schools in England was non-uniform.
NO... More than 40 academies in 2010 failed to reach the government's "floor target" of 30% of pupils with five A*-C GCSEs including maths and English, even though they have school uniforms.

The Guardian. Web. 23 July 2015. http://www.theguardian.com/education/2011/jan/18/school-uniform-results.