On the difficulty of relational concepts among participants with Down syndrome

The aim of the study was to compare the difficulty of relational concepts among participants with and without intellectual disability. The French versions of the Boehm Tests of Basic Concepts Third Edition (Preschool and Kindergarten to 2nd grade) were administered to three groups of 47 participants individually matched on their total raw score on the tests. The first group comprised participants with intellectual disability of undifferentiated etiology, the second, participants with Down syndrome and the third, typical children. Item analyses using the transformed item difficulties method to detect differential item functioning across groups showed that the groups’ rank-orders of item difficulty were highly similar. It is concluded that, all things being equal, relational concepts are of comparable difficulty and follow a similar sequence of development whatever the cognitive and etiological status of participants. Methodological and theoretical implications of these findings are discussed.

► Boehm Tests of Basic Concepts were administered to participants with and without ID.
► Item analyses showed that the groups’ rank-orders of item difficulty were highly similar.
► Relational concepts thus follow a similar sequence of development whatever the cognitive status of participants.
► Results of participants with Down syndrome and of those with ID of undifferentiated etiology are similar.