From an equity perspective, the concern is that disparities in science performance related to students' socio-economic and demographic backgrounds might extend to students' attitudes towards science, including their expectations - or lack thereof - of a career in science or their appreciation of scientific approaches to enquiry. Students' attitudes towards science and their self-beliefs about learning science are discussed in greater detail in Chapters 2 and 3. In PISA, a student's socioeconomic background is estimated by the PISA index of economic, social and cultural status (ESCS), which is based on information about the students' home and background (Box 1.6.1).