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A historical overview of the IEA's language-related studies leading to the implementation of the Progress in International Reading Literacy Studies

This special issue consisting of analyses of the data of the international comparative Progress in International Reading Literacy Studies aims to contribute to the knowledge on reading literacy internationally. This introductory article is a historical overview of the International Association for the Evaluation of Educational Achievement (IEA)'s language- and literacy-related studies. It provides the background for five papers investigating national and cross-national data and the contextual factors that may affect reading literacy across the world. The findings in this issue provide greater insight into the complexity of reading achievement internationally. Furthermore, it illustrates that the data of these studies provide fertile ground for secondary analyses to address a great variety of both nationally and internationally relevant research questions.