Group design research studies can provide evidence to draw conclusions about "what works," "for whom," and "under what conditions" in special education. The quality indicators introduced by Gersten and colleagues (2005) have contributed to increased rigor in group design research, which has provided substantial…

A common motivation for adding control variables to statistical models is to reduce the potential for spurious findings when analyzing non-experimental data and to thereby allow for more reliable causal inferences. However, as I show here, unless "all" potential confounding factors are included in an analysis (which is unlikely to be…

This addendum to previously published results presents alternative analyses of data from large-scale effectiveness studies of Cognitive Tutor Algebra I in middle schools and high schools. These alternative analyses produce results that are substantively the same as previously reported. We find a significant positive effect of 0.21 standard…

This report summarizes the findings of an analysis of a series of action research projects conducted by Goshen Community Schools at the elementary, middle, and high school levels. During the 2008-2009 school year, 40 teachers participated in independent action research studies regarding the extent to which a six step approach to direct vocabulary…

This article presents person-oriented and variable-oriented approaches to data analysis. To illustrate these two approaches and the types of information they provide the researcher, data from 3558 control group youth from the National Cross-Site Evaluation of High Risk Youth Programs were analysed. The relationship, over time, between parent…

Three forms of objective evaluation were used to assess the impact of a nurture group pilot project on the lives of staff and pupils: Boxall Profiles, the Strength and Difficulties Questionnaire, and questionnaires for staff. In addition, a micro study was carried out of two nurture groups using matched control groups. The article provides an…

Eye movements latencies toward peripherally presented stimuli were measured in 10-year-old dyslexic and control children. Dyslexic subjects, previously found to be oversensitive to stimulation of the magnocellular channel, showed reduced latencies as compared to normally reading controls. An attention shifting task was also used which showed no…

Toddlers in the lowest 10th percentile for lexical production were compared with age- and language-matched controls on measures of phonetic complexity, lexical development, and grammatical complexity. Results indicate an overlap between phonology, lexicon, and grammar and suggest the importance of true consonant production for lexical development.…