Education policy in the U.S. in the last two decades has emphasized large-scale assessment of students, with growing consequences for schools, teachers, and students. Given the high stakes of such tests, it is important to understand the relationships between students' answers to test items and their knowledge and skills in the tested content…

Presented at the Annual National Council on Measurement in Education (NCME) in New York in March 2008. This presentation explores how different item weighting can affect the effective weights, validity coefficents and test reliability of composite scores among test takers.