The ethnic differences in educational achievement are clearly visible. Sociological theories take into account both the factors within the educational system and external from it, that may have caused the aforementioned inequality. Firstly, the internal aspects include institutional racism. According to the studies of Gillborn and Yodell (2000), teachers had 'racialised expectations'. These were based on the assumption that black students were expected to pose more discipline problems & behaviour viewed as challenging authority. Subsequently, black students felt like teachers picked on them, which put them off the educational habitus. Additionally, Peter Foster (1990) claimed that the teachers’ negative stereotypes about black pupils caused them to be more likely to be placed in lower streams than students with the same ability, which explains the ethnic differences in educational achievement. Moreover, Jenny Bourne (1994) argued that the fact that schools tend to see black boys as threat and label them negatively, leads to their exclusion. Similarly, Osler (2001) stated that black pupils more likely to suffer from unrecorded unofficial exclusions & internal exclusions. This is important as the studies show that only 1 in 5 excluded pupils achieves 5 GCSEs. This shows how the institutional racism within schools may be one of the significant causes for the ethnic achievement gap. However, this theory has been criticised by sociologists such as Tony Sewell, who claimed that whilst racism has not disappeared from schools, it is not powerful enough to prevent individuals from succeeding. Instead, he believed that the factors external from schools, are more important in shaping the differences in educational achievement.When it comes to the aforementioned external factors, one of the leading sociological explanations for the ethnic differences in educational achievement is the idea of cultural deprivation. This theory is based on the concept that the cultures of ethnic minorities fail to instil the values, norms, skills and knowledge, required by the educational system to achieve. For example, Bereiter and Engelmann argued that the language spoken by low-income black American families is inadequate for educational success. Additionally, there have been claims that black children are socialised into subculture that instils fatalistic, ‘live for today’ attitude, which has no value for the education system, leaving them unequipped for success. Moreover, Moynihan (1965) stated that the fact that, statistically, many black families are headed by a lone mother, means that the children are deprived of sufficient care because the mother struggles financially without the male breadwinner. In turn, this causes them to undergo inadequate socialisation, which is one for the reasons for their underachievement. It has been also argued, by sociologists such as Murray (1984) that the lack of male role-models is yet another cause of black boys’ educational failure. This is a useful theory in understanding the ethnic inequality in educational achievement, however it has also posed a subject to criticisms. Among others, Driver (1977) argued that the cultural deprivation ignores the positive effects of ethnicity on achievement. For example, the high rate of lone parenthood among Black Caribbean families helps to provide girls with positive role models of strong independent women, which advantages their achievement. Similarly, Lawrence (1982) claimed that black pupils do not underachieve because their culture is weak a but as a result of racism. Similarly, Keddie agreed that ethnic minorities are not culturally deprived but culturally different from the ethnocentric school habitus, which is clearly west-centred, considering for example that the national curriculum is ‘specifically British’ as it ignores non-European languages, literature, music, according to David (1993). Therefore, I believe that the factors within the schools in the form of institutional racism and the ethnocentric curriculum, are more important in shaping the differences in educational achievement among ethnic groups.