Student Growth Percentiles (SGPs) increasingly are being used in the United States for inferences about student achievement growth and educator effectiveness. Emerging research has indicated that SGPs estimated from observed test scores have large measurement errors. As such, little is known about "true" SGPs, which are defined in terms…

We use data from a large-scale experiment conducted in Indiana in 2009-2010 to examine the impact of two interim assessment programs (mCLASS and Acuity) across the mathematics and reading achievement distributions. Specifically, we focus on whether the use of interim assessments has a particularly strong effect on improving outcomes for low…

Observational methods are increasingly being used in classrooms to evaluate the quality of teaching. Operational procedures for observing teachers are somewhat arbitrary in existing measures and vary across different instruments. To study the effect of different observation procedures on score reliability and validity, we conducted an experimental…

The authors explored the effects of drifting common items on vertical scaling within the higher order framework of item parameter drift (IPD). The results showed that if IPD occurred between a pair of test levels, the scaling performance started to deviate from the ideal state, as indicated by bias of scaling. When there were two items drifting…