Presented at the national conference for AERA (American Educational Research Association) in April 2009. The large variability of SAT taker population across states makes state-by-state comparisons of the SAT scores challenging. Using a mixture modeling approach, therefore, the current study presents a method of identifying subpopulations in terms…

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.