This study presents a meta-analysis of single-case experimental research on family-implemented interventions for improving the social and other communicative behaviors of individuals with developmental disabilities (DD). A total of 40 studies were included in this meta-analysis. The Tau-U effect size with the Kruskal-Wallis and the Dunn post hoc…

Background music has been found to have beneficial, detrimental, or no effect on a variety of behavioral and psychological outcome measures. This article reports a meta-analysis that attempts to summarize the impact of background music. A global analysis shows a null effect, but a detailed examination of the studies that allow the calculation of…

Robin Lakoff proposed that women are more likely than men to use tentative speech forms (e.g., hedges, qualifiers/disclaimers, tag questions, intensifiers). Based on conflicting results from research testing Lakoff's claims, a meta-analysis of studies testing gender differences in tentative language was conducted. The sample included 29 studies…

The empirical literature investigating general and domain-specific self-concepts of adults with learning disabilities was examined using meta-analytic techniques. Eight inclusion criteria were developed to evaluate this literature and led to the inclusion of 22 studies. Results indicated that adults with learning disabilities reported lower…

Meta-analytic techniques were used to analyze the effects of age, education, and work experience on General Aptitude Test Battery (GATB) validities and test scores. The sample consisted of 30,568 subjects from 143 Specific Aptitude Test Battery (SATB) validation or revalidation studies analyzed since 1972. The effect of these three variables on…

Drawing from work on the meta-analysis of over 500 validation studies of the General Aptitude Test Battery (GATB) by the U.S. Employment Service, the paper presents a methodological message and a substantive message. Gene Glass's methods, as used by Edwin Ghiselli in personnel selection, ignore study artifacts (sampling error, error of…

A meta-analysis of 82 recidivism studies (1,620 findings from 29,450 sexual offenders) identified deviant sexual preferences and antisocial orientation as the major predictors of sexual recidivism for both adult and adolescent sexual offenders. Antisocial orientation was the major predictor of violent recidivism and general (any) recidivism. The…

A meta-analysis of 267 studies conducted between 1950-1980 found that auditory and visual perceptual skills can successfully increase the accuracy of predicting reading achievement, but the magnitude of increases in predictive accuracy was contingent upon the combination of variables studied and was significantly reduced if an IQ score was known.…