2017-2018 Differential Item Functioning (DIF) Analyses Report
DIF analysis is used to investigate whether measures on an assessment instrument functions differently for different groups of children. Examination of DIF is important to determine whether subgroups of children who possess comparable ability levels have equal (or different) likelihood of receiving the same ratings on the measures. This analysis provides evidence that the DRDP (2015) generally functions as intended for all children of the same ability level (i.e., no bias in a specific developmental area or skill). The two subgroups examined are children with disabilities (infants and toddlers with IFSPs and preschool children with IEPs) and children without disabilities.