Throughout the world, equity and excellence in education is a major issue of concern. International comparative studies such as those carried out by OECD (PISA) have launched a worldwide debate on the effectiveness of educational systems (macro level), schools (meso level) and teachers (micro level) in terms of enhancing equity and excellence. Inspired by the OECD research and spurred by national policy-making, quantitative and qualitative research studies have recently been conducted in different parts of the globe aiming to provide deeper insight into the crucial variables that have an...