streaming in schools

I fully agree with the fact that streaming may not allow slower students to reach their full potential and may disadvantage them because they need the experience from their other classmates who are at higher levels and can encourage them to strive better rather than putting the slower children in classes where they may not be to help each other because they are all at the same level "fighting". When there are mixed abilities in one class there is a vast improvement mentally and psychologically. As a teacher, there may not be a choice because of how principals may assign u to a class but I really think that slower children should not be separated from the other students.My view came from looking at the site: http://www.nzherald.co.nz/secondary-education/news/article.cfm?c_id=315&objectid=10511173&pnum=1