Abstract
The aim of this study was to explain differences between pupils’ achievements in composition. A theoretic causal model of factors of importance to pupils’ proficiency in writing has been tested with data collected in the Swedish part of the IEA‐study. These data involve the pupils’ sociocultural background, the teachers’ experiences and the teaching of writing. The pupils’ marks for an argumentative composition represent the standard of their achievement in writing. The present analysis includes pupils in grade 9 of the Swedish compulsory comprehensive school. The causal model was verified concerning the relationships between pupils’ sociocultural background and their writing achievement. However, no relationships could be found between teaching in school and pupils’ achievement, a result which is discussed critically.