Language-related DIF in the WASL Mathematics test

This study was conducted to determine whether the Mathematics tests of the Washington Assessment of Student Learning (WASL) contain evidence of bias against students who are English language learners (ELL). Mantel-Haenszel and SIBTEST procedures were implemented on two years of data from 4 th and 7th grades to test for evidence of both item and bundle-level differential item functioning (DIF). Results showed that differences in mathematics scores between accommodated ELL and non-ELL students were a function of DIF related to item type in the 4th grade, but differences in 7th grade scores were primarily due to impact or true differences in mathematics proficiency. These results have implications for mathematics assessment reform in Washington State.