Recent years have witnessed a considerable increase in the interest in international reading literacy studies, such as PISA. The results of these studies, in turn, are often the basis on which nations make educational decisions today. But to what extent are the results reliable and valid? To what extent are the decisions based on them fair and well-founded? The answer lies largely in the quality of the translations used in these studies - in the extent to which the texts and translations used in these studies are equivalent to each other and thus equally easy or difficult to read. This study examines the special problems that arise when translating texts in international reading literacy studies, where equivalence of difficulty between all the different-language reading texts is a key prerequisite for the validity of the entire test. To this end, three English texts and their Finnish translations used in the OECD PISA 2000 pilot test are analysed and compared linguistically from the point of view of text difficulty. The book will thus provide important reading for all those involved or interested in international student assessments, especially those of reading literacy.