Teachers use stereotypical notions of ability to stream students, less likely to see working class and black students as having ability to succeed, these students more likely placed in lowest streams and entered for lower tier GCSEs
Leads to an 'A to C economy' in schools, where schools focus time and resources on students they see as having potential to get 5 A*-C grades to boost league table position
Schools categorise students into 3 types: 1) Those who will pass anyway, 2) Those with potential who will be helped to get a grade C or better, 3) Hopeless cases doomed to fail