Numeracy and literacy skills have become increasingly important in modern labour markets. The large gender differences that several studies have identified have therefore sparked considerable attention among researchers and policy makers. Little is known about the moment in which such gaps emerge, how they evolve and if their evolution differs…

An outline is given of the context in which The International School Effectiveness Research Project (ISERP) was designed and it is argued that the deficiencies of existing studies and the increased internationalization of education makes the more rigorous approach of ISERP essential. A number of methodological lessons from the study are given,…