The aim of this research was to determine to what extent GCSE examination results differ between schools. The data were collected from 65 schools in six inner London education authorities in 1990, and were analysed using multilevel value added analysis. Some teaching materials using these data have been developed. Details are available at the following website: <a href=http://tramss.data-archive.ac.uk> http://tramss.data-archive.ac.uk</a> . The variables recorded are: GCSE examination scores for English and mathematics; a combined examination score from all subjects; pupil and school identifiers (numerical only); school gender (mixed, boys or girls school); pupil gender; continuous intake measure of reading ability; categorical intake measure of verbal reasoning ability. percentage of children in a school on free school meals, an indicator for social deprivation.