To evaluate the veracity of models of the mere exposure effect and to understand the processes that moderate the effect, we conducted a meta-analysis of the influence of repeated exposure on liking, familiarity, recognition, among other evaluations. We estimated parameters from 268 curve estimates drawn from 81 articles and revealed that the mere exposure effect was characterized by a positive slope and negative quadratic effect consistent with an inverted-U shaped curve. In fact, such curves were associated with (a) all visual, but not auditory stimuli; (b) exposure durations shorter than 10 s and longer than 1 min; (c) both homogeneous and heterogeneous presentation types; and (d) ratings that were taken after all stimuli were presented. We conclude that existing models for the mere exposure effect do not adequately account for the findings, and we provide a framework to help guide future research. (PsycINFO Database Record

A task force of experts was convened by the American Psychological Association (APA) to update the knowledge and policy about the impact of violent video game use on potential adverse outcomes. This APA Task Force on Media Violence examined the existing literature, including the meta-analyses in the field, since the last APA report on media violence in 2005. Because the most recent meta-analyses were published in 2010 and reflected work through 2009, the task force conducted a search of the published studies from 2009-2013. These recently published articles were scored and assessed by a systematic evidentiary review, followed by a meta-analysis of the high utility studies, as documented in the evidentiary review. Consistent with the literature that we reviewed, we found that violent video game exposure was associated with: an increased composite aggression score; increased aggressive behavior; increased aggressive cognitions; increased aggressive affect, increased desensitization, and decreased empathy; and increased physiological arousal. The size of the effects was similar to that in prior meta-analyses, suggesting a stable result. Our task force concluded that violent video game use is a risk factor for adverse outcomes, but found insufficient studies to examine any potential link between violent video game use and delinquency or criminal behavior. Our technical report is the basis of this article. (PsycINFO Database Record

Quantitative research literature is often biased because studies that fail to find a significant effect (or that demonstrate effects in an undesired or unexpected direction) are less likely to be published. This phenomenon, termed publication bias, can cause problems when researchers attempt to synthesize results using meta-analytic methods. Various techniques exist that attempt to estimate and correct meta-analyses for publication bias. However, there is no single method that can (a) account for continuous moderators by including them within the model, (b) allow for substantial data heterogeneity, (c) produce an adjusted mean effect size, (d) include a formal test for publication bias, and (e) allow for correction when only a small number of effects is included in the analysis. This article describes a method that we believe helps fill that gap. The model uses the beta density as a weight function that represents the selection process and provides adjusted parameter estimates that account for publication bias. Use of the beta density allows us to represent selection using fewer parameters than similar models so that the proposed model is suitable for meta-analyses that include relatively few studies. We explain the model and its rationale, illustrate its use with a real data set, and describe the results of a simulation study that shows the model's utility. (PsycINFO Database Record

While teacher effectiveness has been a particular focus of federal education policy, and districts allocate significant resources toward professional development for teachers, these efforts are guided by an unexplored assumption that classroom practice can be improved through intervention. Yet even assuming classroom practice is responsive, little information is available to inform stakeholder expectations about how much classroom practice may change through intervention, or whether particular aspects of classroom practice are more amenable to improvement. Moreover, a growing body of rigorous research evaluating programs with a focus on improving classroom practice provides a new opportunity to explore factors associated with changes in classroom practice, such as intervention, study sample, or contextual features. This study examines the question of responsiveness by conducting a meta-analysis of randomized experiments of interventions directed at classroom practice. Our empirical findings indicate that multiple dimensions of classroom practice improve meaningfully through classroom practice-directed intervention, on average, but also find substantial heterogeneity in the effects. Implications for practice and research are discussed.

Some experimental designs involve clustering within only one treatment group. Such designs may involve group tutoring, therapy administered by multiple therapists, or interventions administered by clinics for the treatment group, whereas the control group receives no treatment. In such cases, the data analysis often proceeds as if there were no clustering within the treatment group. A consequence is that the actual significance level of the treatment effects is larger (i.e., actual p values are larger) than nominal. Additionally, biases will be introduced in estimates of the effect sizes and their variances, leading to inflated effects and underestimated variances when clustering in the treatment group is not taken into account. These consequences of clustering can seriously compromise the interpretation of study results. This article shows how information on the intraclass correlation can be used to obtain a correction for biases in the effect sizes and their variances, and also to obtain an adjustment to the significance test for the effects of clustering.