This research explored the measurement characteristics of two science examinations and the potential to use access arrangements data to investigate how students requiring reading support are affected by features of exam questions. For two science examinations, traditional and Rasch analyses provided estimates of difficulty and information on item functioning. For one examination, the performance of students eligible for support from a reader in exams was compared to a "norm" group. For selected items a sample of student responses were analysed. A number of factors potentially making questions easier, more difficult or potentially contributing to problems with item functioning were identified. A number of features that may particularly influence those requiring reading support were also identified. (Contains 5 figures, 8 tables and 5 notes.)