Investigating Differential Item Functioning Across English and Indigenous Languages in South Africa Using PIRLS 2021 Data

• In Event: AERA Roundtable Session Thursday 7:45 am - Gold 4
  In Roundtable Session: Measurement Invariance and Differential Item Functioning in Educational Assessment

Abstract

This study examines Differential Item Functioning (DIF) across English, isiXhosa, and isiZulu versions of the PIRLS 2021 “Library Mouse” passage to assess linguistic equity in South Africa’s multilingual educational context. Using logistic regression DIF detection in R, item performance for fourth-grade students (N = 4,309) is compared across multiple-choice and constructed-response formats. Higher DIF is anticipated in constructed-response items due to expressive language demands and translation variability. Findings will clarify whether observed score differences reflect true ability or construct-irrelevant variance linked to language. This research advances psychometric validity, multilingual test design, and language policy, offering implications for equitable assessment practices and improved approaches to handling linguistic diversity in international large-scale assessments.

Authors

• John Baffoe, University of Wisconsin-Milwaukee

• Bo Zhang, University of Wisconsin - Milwaukee