Educational researchers commonly use the rule of thumb of "design effect smaller than 2" as the justification of not accounting for the multilevel or clustered structure in their data. The rule, however, has not yet been systematically studied in previous research. In the present study, we generated data from three different models…

Conceptual rationales from five research contexts are presented, which all posit unmeasured variables that interact with observed independent variables to produce a complete model of the dependent variable. Strategies for overcoming related difficulties are outlined, including increased longitudinal assessment, oversampling of levels of…

Researchers persist in using stepwise regression in spite of problems with this approach. As noted by B. Thompson (1995), three problems accompany the use of stepwise applications. The first is that computer packages may use incorrect degrees of freedom in their computations, resulting in a greater likelihood of obtaining a spurious statistical…

The serious problems associated with the use of stepwise methods are well documented. Various authors have leveled scathing criticisms against the use of stepwise techniques, yet it is not uncommon to find these methods continually employed in educational and psychological research. The three main problems with stepwise techniques are: (1)…

This study found that accuracy in predicting the out-of-home placement of children with severe disabilities increased little in a large cross-sectional sample (n=5,992) over a smaller semilongitudinal sample (n=141). Factors such as age, adaptive and maladaptive behavior, and ethnicity are discussed. (Author/JDD)

Approaches to studying the relationships between stress and school organizational sources of stress were examined. Rather than sampling a number of schools and school average data indicating school health and stress levels in these schools, simple teacher samples and teacher-level analyses were used. For a sample of 1300 high school teachers in…