A descriptive analysis of research practices and a meta-analysis of control group effect sizes are used to address Hawthorne effects in educational experiments. The analysis of 86 studies and 256 treatment/Hawthorne/no-treatment control group effect size comparisons indicate that artifact controls have limited utility in dealing with the Hawthorne…

Techniques are presented for use in meta-analysis to obtain effect sizes when information is missing from the original report. A method of reconstructing the mean squares within groups is presented for one-way analysis of variance and factorial designs. (SLD)

Three sets of meta-analyses examined gender effects on children's language use. Each set of analyses considered an aspect of speech that is considered to be gender typed: talkativeness, affiliative speech, and assertive speech. Statistically significant average effect sizes were obtained with all three language constructs. On average, girls were…

This study provides a correlational meta-analysis of 65 independently written or published studies on teacher stress between 1998 and 2003. We measured the relationships between teacher stress and numerous other constructs including coping, burnout, emotional responses, personality mediators, personal support, environmental structure, and…

Narrative reviews have raised several questions regarding the predictive validity of the Hare Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 2003) and related scales in institutional settings. In this meta-analysis, the authors coded 273 effect sizes to investigate the association between the Hare scales and a hierarchy of increasingly specific…

The efficacy of (cognitive) behavioral therapy ([C]BT) for generalized anxiety disorder was investigated and compared with the efficacy of pharmacological therapy using meta-analytic techniques. A total of 65 (C)BT studies and pharmacological studies were included. (C)BT was more effective than control conditions. The results of the comparison…

A meta-analysis of 58 studies was performed in which IQ, academic achievement, and behavior characteristics were examined across students with learning disabilities (LD), mild intellectual disabilities (MID), and emotional/behavioral disabilities (E/BD). The effect sizes between students with LD and MID were the largest in the domains of IQ and…

A comprehensive meta-analysis of the research following Glass, McGraw, and Smith's (1981) technique integrated findings from twenty-five comparative studies from 1990 to 2003 targeting student achievement and distance education in allied health professions. Student achievement was assessed through course grades and resulted in an overall effect…

A meta-analytic study on effectiveness of behavioral and psychotherapeutic treatments for challenging behaviors in individuals with mild mental retardation is reported. Eighty articles were examined. For each comparison, several study variables and two effect sizes (percentage of nonoverlapping data--PND and percentage of zero data--PZD) were…

This meta-analysis reviews experimental and quasi-experimental studies in which students learned by constructing, modifying, or viewing node-link diagrams. Following an exhaustive search for studies meeting specified design criteria, 67 standardized mean difference effect sizes were extracted from 55 studies involving 5,818 participants. Students…

Objective: A meta-analysis was conducted to evaluate the ability of parent training programs to reduce parents' risk of abusing a child. Method: A total of 23 studies were submitted to a meta-analysis. Outcomes of interest included parents' attitudes toward abuse, emotional adjustment, child-rearing skills, and actual abuse. Conclusions:…

Schools and districts are adopting out-of-school-time (OST) programs such as after-school programs and summer schools to supplement the education of low-achieving students. However, research has painted a mixed picture of their effectiveness. To clarify OST impacts, this synthesis examined research on OST programs for assisting at-risk students in…

Methods for meta-analysis have evolved dramatically since Gene Glass first proposed the term in 1976. Since that time statistical and nonstatistical aspects of methodology for meta-analysis have been developing at a steady pace. This guide is an attempt to provide a practical introduction to rigorous procedures in the meta-analysis of social…

This article finds the empirical review of the intellectual effects of family factors by Lala Carr Steelman wanting because (1) it is selective and incomplete; (2) it ignores systematic aggregate effects; (3) it imposes linear analysis on nonmonotone relationships; and (4) it disregards most of the confounds identified by Steelman as crucial.…

The author responds to criticism by R. B. Zajonc on a review of the extant literature on the intellectual consequences of sibship size and birth order. (Author/LMO)