PARA Accessible Reading Assessment Reports: Examining Differential Distractor Functioning in Reading Assessments for Students with Disabilities


A report examining the incorrect response choices, or distractors, of students with disabilities in standardized reading assessments. Differential distractor functioning (DDF) analysis differs from differential item functioning (DIF) analysis, which treats all answers alike and examines all wrong answers against the correct answer. DDF analysis, in contrast, examines only the wrong answers. If different groups, such as students with disabilities and students without disabilities, preferred different incorrect responses to an item, then the item could mean something different to the different groups. The authors found items showing DDF for students with disabilities in grade 9, but not for grade 3. Results also suggest that items showing DDF were more likely to be located in the second half of the assessments rather than the first half. Additionally, results suggest that in items showing DDF, students with disabilities were less likely to choose the most common distractor than their non-disabled peers. Results of this study can shed light on potential factors affecting the accessibility of reading assessments for students with disabilities.


January 2007 
Partnership for Accessible Reading Assessment (PARA)
National Center on Educational Outcomes (NCEO)


  • Specific life stage
    • Children
    • Adolescents and young adults
  • Educational accountability and assessment
    • Students with Disabilities