Replicating previously reported empirical research is a necessary aspect of an evidence-based field of special education, but little formal investigation into the prevalence of replication research in the special education research literature has been conducted. Various factors may explain the lack of attention to replication of special education…

The paper discussed the difficulties and problems in experimental researches in educational technology, such as misunderstanding in teachers' concept, disjointedness between theory and practice, inadequate understanding of dialectics in experimental educational technology researches, research project selection and theoretical hypothesis formation…

An experiment is described which uses a real-world sample of lawn fertilizer in a simple exercise to illustrate problems associated with the sampling step of a chemical analysis. A mixed-particle fertilizer containing discrete particles of iron oxide (magnetite, Fe[subscript 3]O[subscript 4]) mixed with other particles provides an excellent…

This article discusses the use of propensity scoring in experimental program evaluations to estimate impacts for subgroups defined by program features and participants' program experiences. The authors discuss estimation issues and provide specification tests. They also discuss the use of an overlooked data collection design--obtaining predictions…

Group-randomized trials (GRTs)--studies that evaluate the efficacy or effectiveness of interventions occurring at the group level--are increasingly used to assess the effects of school-based prevention programs on behavioral outcomes of children and adolescents. These designs pose many implementation and design challenges for school…