Student growth percentiles (SGPs) are currently used by several states and school districts to provide information about individual students as well as to evaluate teachers, schools, and school districts. For SGPs to be defensible for these purposes, they should be reliable. In this study, we examine the amount of systematic and random error in…

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…