Aptitude measurement: is measurement validity compromised in the morning

The purpose of the present study was to evaluate reliability and validity General Aptitude Test (GAT), a national instrument for measurement aptitude/achievement in Kingdom Saudi Arabia as function daytime testing. Participants were 722 students who took on GAT across morning evening administrations within-person pre-post design. matched gender, parental education, test center characteristics (i.e., size). tested its psychometric properties invariance time day. Results pointed significant misfit using an exact protocol. Specifically, there large number non-invariant items pointing Differential Item Functioning (DIF). Second, internal consistency reliabilities consistently lower during testing compared evidenced both statistical visual means. Concerns about dimensionality also raised administration. Last, comparison performance levels indicated that associated with decrements all domains results have implications public policy if administration is compromised.