Differential Item Functioning for Boys and Girls in a Screening Instrument for Attention Deficit Hyperactivity Disorder.

Differential item functioning (DIF) indicates differential response probabilities of items for different subgroups. While there is a vast amount of research and literature on DIF in the field of educational screening and career assessment, DIF analysis has hardly been applied in the field of clinical assessment. This paper aims at analyzing the presence of gender related DIF in a cross-sectional survey of children assessed by a structured questionnaire containing items on attention deficit and hyperactivity. A total of 1449 children (mean age: 1.94 ± 0.14 years; 51.2% male) were included. Almost no significant variations in parameters were found between boys and girls. Results based on a Partial Credit Model indicate an absence of DIF in eight out of nine items. Consistent with other studies in attention deficit hyperactivity disorder (ADHD) our results imply that the same level of rating for a symptom has the same meaning for boys and girls.