English As a Second Language Reading Strategies:: a Confirmatory Approach to Differential Item Functioning

The study described in this text was undertaken to test the hypothesis that reading comprehension items, which elicit specific bottom-up and top-down strategies, favour certain linguistic/cultural groups. Although a variety of statistical methods have been developed for flagging test items that function differentially for equal ability examinees from different ethnic, linguistic, or gender groups, the standard differential item functioning (DIF) detection procedures have not been very useful in explaining why DIF occurs. To address this problem, a confirmatory approach to DIF was used to determine whether groups of reading test items, classified according to a bottom-up, top-down reading strategy framework, functioned differentially for equal ability Arabic and Mandarin ESL learners. Analyses revealed systematic group differences in two of the bottom-up and three of the top-down reading strategy categories. These results demonstrate the utility of employing a theoretical framework for interpreting group differences on a reading test that can be used to assist ESL reading researchers, test developers, and instructors in the development of technically sound reading assessments.