Fifty years of theory and research offer increasing levels of support for the assertion that principal leadership makes a difference in the quality of schooling, school development, and student learning. In the current context of global education reform, however, recent inquiries have focused on identifying how teams of school leaders contribute…

The present meta-analysis examines the effect of grade retention on academic outcomes and investigates systemic sources of variability in effect sizes. Using multilevel modeling (MLM), the authors investigate characteristics of 207 effect sizes across 22 studies published between 1990 and 2007 at two levels: the study (between) and individual…

The purpose of this report is to provide an update on the state of the research on testing accommodations, as well as to identify promising areas of research to further clarify and enhance understanding of current and emerging issues. The research described encompasses empirical studies of score comparability and validity studies, as well as…

Best-evidence synthesis was used to review 29 research papers published in English that evaluate the effects of ability grouping on student achievement in secondary schools. Six randomized experiments, 9 matched experiments, and 14 correlational studies were reviewed. Findings do not indicate beneficial effects of ability grouping on achievement.…

One of the most important effect sizes used in meta-analysis is the standardized mean difference (SMD). In this article, the conditions under which SMD effect sizes based on different measures of the same construct are directly comparable are investigated. The results show that SMD effect sizes from different measures of the same construct are…

Meta-analytic research techniques were used to compare the General Aptitude Test Battery (GATB) validities of blacks and non-minorities. The sample consisted of 7,854 black and 15,769 non-minority subjects from 113 Specific Aptitude Test Battery (SATB) validation studies analyzed since 1972. The first approach was to compare average validities…

Classical measurement theory was used to investigate measurement characteristics of both parts of the Finding Embedded Figures Test (FEFT) when the test was: administered in either a "no guessing" supply format or a multiple-choice selection format; administered to either undergraduate college students or middle school students; and…