In international large-scale assessments, students may not be compelled to answer every test item: a student can decide to skip a seemingly difficult item or may drop out before the end of the test is reached. The way these missing responses are treated will affect the estimation of the item difficulty and student ability, and ultimately affect…

Assessing the achievement of students in elementary and secondary schools and the nation's educational progress is fundamental to informing education policy approaches. Congressional interest in this area includes and extends beyond the annual assessments administered by states to comply with the educational accountability requirements of Title…