Value-added modeling (VAM), one class of statistical models used to estimate individual teacher's or school's contribution to student achievement based on student test score growth between consecutive years, has become increasingly popular in the last decades. Despite the increasing popularity of VAM, many researchers are concerned about the…

High-quality measures of instructional practice are essential for research and evaluation of innovative instructional policies and programs, as well as for providing feedback to teachers and administrators. In this study, the authors examined whether using anchoring vignettes in web-based surveys improved the validity of teachers' self-assessments…