Over time international large-scale assessments have grown in terms of number of studies, cycles, and participating countries, many of which are a heterogeneous mix of economies, languages, cultures, and geography. This heterogeneity has meaningful consequences for comparably measuring both achievement and non-achievement constructs, such as…

When using IRT models in Educational Achievement Testing, the model is as a rule too simple to catch all the relevant dimensions in the test. It is argued that a simple model may nevertheless be useful but that it can be complemented with additional analyses. Such an analysis, called profile analysis, is proposed and applied to the reading data of…

In the Programme for International Student Assessment (PISA) the items are organised in small clusters relating to the same stimulus material (called 'units'). Homogeneity analysis (HA) is used to develop a detailed description of the relationship between all the items in one unit, using the categorical information available in the PISA data. The…

In this paper we have set out to search for similarities and differences between the Nordic countries concerning patterns of competencies defined as scientific literacy in the Programme for International Student Assessment (PISA) study. The first part focuses on gender differences concerning the two types of competencies, understanding of…