Development and Calibration of Chemistry Items to Create an Item Bank, using the Rasch Measurement Model

This article describes the development and calibration of items from the 1997 to 2006 Tertiary Entrance Exams (TEE) in Chemistry conducted by the Curriculum Council of Western Australia for the purposes of establishing a Chemistry item bank. Only items that met the strict Rasch measurement criterion of ordered thresholds were included. Item Residuals and Chi-square conformity of the items were likewise scrutinized. Further, specialist experts in chemistry were employed to ascertain the qualitative properties of the items, particularly the item wording, so as to provide accurate item descriptors. An item bank of 174 items was created. This item bank may now be accurately used by teachers in their classrooms for the purposes of developing class assessments in Chemistry and/or for classroom diagnostic purposes.