Explanatory patterns regarding situational differences in reading comprehension performance may be best captured by multidimensional reader profiles. Data from 56 third- and fifth-grade students were collected to investigate the applicability, scope, and convergent validity of a reader profiling scheme based on Alexander's (2005) reader profile…

Background: Cluster randomized experiments that assign intact groups such as schools or school districts to treatment conditions are increasingly common in educational research. Such experiments are inherently multilevel designs whose sensitivity (statistical power and precision of estimates) depends on the variance decomposition across levels.…