Randomized experiments involving education interventions are typically implemented as cluster randomized trials, with schools serving as clusters. To design such a study, it is critical to understand the degree to which learning outcomes vary between versus within clusters (schools), specifically the intraclass correlation coefficient. It is also…

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…

When evaluators plan site-randomized experiments, they must conduct the appropriate statistical power analyses. These analyses are most likely to be valid when they are based on data from the jurisdictions in which the studies are to be conducted. In this method note, we provide software code, in the form of a SAS macro, for producing statistical…

Research in fields other than education has found that studies with small sample sizes tend to have larger effect sizes than those with large samples. This article examines the relationship between sample size and effect size in education. It analyzes data from 185 studies of elementary and secondary mathematics programs that met the standards of…

Article discussed the relevance for educational research found in the Type 11 error, one identified as a correct rejection of a 2-tailed test of hypothesis followed by an incorrect directional decision. (Author/RK)

In a previous paper (Hartley and Holt, 1971) the development of a three-minute reasoning test was described, and its validity and reliability assessed. In this paper three experiments are reported which look in greater detail at these aspects of the test in different situations. (Author)

Documenting treatment integrity is an important issue in research and practice in any discipline concerned with prevention and intervention. However, consensus concerning the dimensions of treatment integrity and how they should be measured has yet to emerge. Advances from three areas in which significant treatment integrity work has taken…

The study attempted to measure the impact of diverse instructional methods on individuals whose learning styles tended to fall along a concrete-symbolic continuum as measured by a learning activities questionnaire. Two assumptions were made: (1) those with highly concrete learning styles learn best by direct contact type activities and (2)…