Experimental evaluations that involve the educational system usually involve a hierarchical structure (students are nested within classrooms that are nested within schools, etc.). Concerns about contamination, where research subjects receive certain features of an intervention intended for subjects in a different experimental group, have often led…

The authors conducted an experiment during the 2003-2004 school year to determine whether "On Our Way to English" ("OWE"), a product to help elementary students learn to read and speak English, was more effective in a California and a Texas school district than materials already in place. In the California study, 384 English…

The authors were asked to find out whether "On Our Way to English" ("OWE"), a supplementary, text-based product to help elementary school students learn to read and speak English was more effective in a California and a Texas school district than the materials the districts already had in place. They conducted an experiment…