Items flagged as DIF in booklet comparisons displayed non-uniform DIF in their item characteristic curves¶

Claim · All claims
Evidence · 1 study · associational r2 · q2
Currency · newest study 2021 · not yet checked against its sources · not reviewed by a person · overdue for a recheck since 2024: tool and model accuracy changes quickly

Subclaims¶

q2 i? ICCs of items flagged as DIF by both methods showed non-uniform DIF, with the advantage between booklets changing across the ability continuum. → Soysal 2021

Evidence¶

Soysal 2021¶

Soysal, S., & Yilmaz Kogar, E. (2021). An Investigation of Item Position Effects by Means of IRT-Based Differential Item Functioning Methods. International Journal of Assessment Tools in Education, 8(2), 239-256. https://doi.org/10.21449/ijate.779963

q2 · i? · associational · r2

ICCs were examined for items flagged as DIF in all method-by-purification conditions; four items (item 6 vs Booklet B, items 13 and 16 vs Booklet C, item 10 vs Booklet D) were plotted, and the article reports "these items displayed non-uniform DIF."

"It could be observed in Figure 1 that these items displayed non-uniform DIF."

Discussion¶

Related Claims¶

• ICC method flags seven items with the largest DIF indices, two of which show slight nonuniform DIF that the unsigned-area measure understates — reports the opposite
• The ICC and LDF methods identify substantially different sets of items as exhibiting DIF on a state science performance assessment — related
• Given assumption violations and the uniformity factor, the authors judge the LDF method more likely accurate and superior to ICC for this performance assessment — related
• Lord's chi-square identified more DIF items than Raju's unsigned area in the without-purification condition — related