Validation of a High-Stakes Test: GA IESOL Listening Unit

The purpose of this study is the validation of the GA Classic IESOL examination at CEFR level B2 (Reading, Listening, Writing and Speaking), as a criterion-referenced achievement test, using the multi-trait, multi-method approach. The data analysed at the moment pertain to the Listening unit and have been studied to examine the content validity, reliability of the scores and unidimensionality of the construct. The Listening unit consists of three tasks (22 items) in four different versions (D-E-F-G). Four separate statistical analyses were performed and all revealed excellent values of internal consistency. As for unidimensionality of the construct, excellent values were revealed for versions E, F and G and acceptable for version D. Similar analyses on the reading test are planned, with the aim of reaching a multitrait-multimethod analysis of the examination as a whole. Further steps of the study will be the IRT equating procedure of the four versions.