Subject and Keywords:
The article demonstrates the consequences on validity when test items are misclassified as constructed-response but in fact function as selected-response. From the review of items included in the scientific part of the national exam (2002–11) that concludes 3-year lower secondary school, 9 items, which were classified as constructed-response but functioning in content and psychometrically as selected-response, were identified. One such item was examined in a case study using IRT modelling. The study showed how guessing of correct responses to items might influence test validity when using an incorrectly classified format.