Effects of Socio-economic Status on Reading Achievement at Collective and Individual Levels in Sweden in 1991 and 2001

The main aim of the study is to examine the changes in the strength of the effects of socio-economic status (SES) on reading achievement at the school, class and individual levels over the last decade in Sweden. This aim is pursued through comparisons between the IEA Reading Literacy Study 1991 (RL 1991) and the repetition of this study in the so called the 10-Year Trend Study (RL 2001). Three aspects are focussed upon, namely changes in the measurement properties of reading achievement, changes in the measurement properties of SES, and changes in the strength of SES effects on reading achievement. Attempts also are made to explore the factors that account for such variations and changes. One of the central questions is whether or not the decentralization reform in education and other social and economic changes in Sweden during the last decade influence the variance distribution and measurement properties of reading and SES, and the strength of SES effects on reading achievement? It is hypothesized that the reading variance between classes and schools may be greater in RL 2001 than in RL 1991, and that the strength of the school SES effect increases over time. These hypotheses will be tested with data from RL 1991 and RL 2001 studies. Data analyses will be carried out by two-level multi-group models in the context of structural equation modelling.