Inquiry-based science instruction is widely advocated, but studies based on international large-scale assessments often show inquiry to be negatively associated with achievement. We re-examine this issue by examining whether the association between inquiry and learning depends upon the provision of teacher guidance. Participants were 151,721…

Teachers are the most important school resource. In every country, teachers' salaries and training represent the greatest share of expenditure on education; and this investment in teachers can have significant returns. Research shows that being taught by the best teachers can make a real difference in the learning and life outcomes of otherwise…

Modern international studies of educational achievement have grown in terms of participating educational systems. Accompanying this development is an increase in heterogeneity, as more and different kinds of educational systems take part. This growth has been particularly pronounced among low-performing, less economically developed systems.…