This paper examines the extent that material, social, and cultural resources and schools account for the relationship between socioeconomic background and student achievement among 15-year-olds in 30 countries. Generally, cultural factors play a more important role in most countries although in a small minority of countries, material resources have a substantial impact. Most often, social resources have little impact. In many countries, educational differentiation—that is, school tracks and school types, and curriculum tracking within schools—mediates the relationship between socioeconomic background and student achievement. Countries with highly tracked systems tend to show stronger relationships. On average, over 60% of the effect of socioeconomic background on achievement is accounted for by these factors. These findings are independent of whether achievement in reading, mathematics, or science is examined. The implications of this study for reducing socioeconomic inequalities in education are discussed.

In most countries, girls perform better than boys in reading but worse in mathematics. However, there is much variation between countries. Explanations for the gender gaps include the organisation of the school system, students' expectations and macro‐societal factors. The purpose of this paper is to account for gender differences in both reading and mathematics among 15‐year‐old students using data from the OECD's 2000 Programme for International Student Assessment (PISA) project. In most countries, school system factors are associated with the gender gap in reading but not in mathematics. Generally, gender differences in students' occupational expectations do not account for the gender gaps, although expectations contribute to the gender gaps in reading in New Zealand and the United States. Although several macro‐societal factors—the proportion of women in the workforce, societal inequality and public sector spending—are associated with the gender gap in reading, the correlations are only moderate, unstable and, importantly, are not associated with the gender gaps in mathematics. The much stronger association between the gender gaps in reading and mathematics across countries implies that they are both influenced by policy: the extent that countries have successfully implemented policies to promote the educational outcomes of girls and young women. In such countries the gender gap in mathematics is small or non‐existent but the gender gap in reading is relatively large. Policies shift both gender gaps in tandem.

Both national and international studies of education often show that the performance of immigrant students is substantially lower than that of non-immigrant students. This article investigates the contribution of socio-economic, sociocultural and school factors to the relative performance of first- and second-generation immigrant students in twenty countries using data from the OECD's 2000 Program for International Student Assessment. In most countries, socio-economic factors substantially account for the weaker performance of immigrant students, whereas sociocultural factors contribute little and school factors are important in only a limited number of instances. Altogether, these factors account for the bulk of the difference in achievement between immigrant and non-immigrant students in almost all the countries examined.

This article focuses on two questions relating to social class inequalities in education: cross-national differences and the contribution of material, cultural and school factors in accounting for the relationship. These questions are addressed using the EGP measure of occupational class and student performance in reading literacy in 30 countries. The pattern of cross-national differences is more closely associated with indicators of modernization and the organization of the school system, rather than indicators of overall societal inequality and economic development. Both material and cultural factors contribute to the relationship between class background and student achievement with cultural factors marginally more important overall. In countries with highly tracked school systems, schools mediate the relationship in that children from lower class backgrounds are more likely to attend lower performing schools. However, the inverse is not true: school differences in student performance are only partially accounted for by class background and other socioeconomic factors.