Extended test time for English learners: Does use correspond to score comparability?

Abstract When large-scale assessment programs are developed and administered in a particular language, students from other native language backgrounds may experience considerable barriers to appropriate measurement of the targeted knowledge and skills. Empirical work is needed to determine if one of the most commonly-applied accommodations to address language barriers, namely extended test time limits, corresponds to score comparability for students who use it. Prior work has examined score comparability for English learners (ELs) eligible to use extended time on tests in the United States, but not specifically for those who more specifically show evidence of using the accommodation. NAEP process data were used to explore score comparability for two groups of ELs eligible for extended time: those who used extended time and those who did not. Analysis of differential item functioning (DIF) was applied to examine potential item bias for these groups when compared to a reference group of native English speakers. Items showing significant and large DIF were identified in both comparisons, with slightly more DIF items identified for the comparison involving ELs who used extended time. Item location and word counts were examined for those items displaying DIF, with results showing some alignment with the notion that language-related barriers may be present for ELs even when extended time is used. Overall, results point to a need for ongoing consideration of the unique needs of ELs during large-scale testing, and the opportunities test process data offer for more comprehensive analyses of accommodation use and effectiveness.