Many tests used in educational settings to identify learning difficulties endeavour to pick up only the lowest performers. Yet these tests are generally developed within a Classical Test Theory (CTT) paradigm that assumes that data do not have significant skew. Rasch analysis is more tolerant of skew and was used to validate two newly developed…

The research project presented in this article was set in the Swedish school context and carried out on a set of compulsory national tests for English, Swedish, and mathematics used at the end of compulsory school. The aims were: (a) to gain a deeper knowledge of the internal structure of the tests and (b) to separate individual performance from…