Linguistic Influences on Differential Item Functioning For Second Language Learners on the National Assessment of Educational Progress

Abstract

Education policy in many countries has undergone changes regarding the testing of English Language Learners (ELLs1), who by definition are not yet proficient in the language of the test. As policies mandate the inclusion of ELLs in large-scale testing, many question the validity of achievement test scores because the degree to which the test score is a function of language proficiency is not clearly understood. This study investigated differential item functioning (DIF) on the National Assessment of Educational Progress (NAEP) between a group of second-language English learners and native English speakers. A linguistic analysis of test items was used as external criteria to understand differences in test item functioning. No DIF was found. To further investigate how language factors affect test scores for ELLs, there is a need for access to larger databases of ELLs with multiple, well-defined measures of English proficiency.