Heterogeneity is commonplace in meta-analysis. When heterogeneity is found, researchers often aim to identify predictors that account for at least part of such heterogeneity by using mixed-effects meta-regression models. Another potentially relevant goal is to focus on the amount of heterogeneity as a function of one or more predictors, but this…

This systematic review evaluated the effects of foreign tact training on emergent learning outcomes in ten published studies. We also conducted a meta-analysis of aggregate data from seven studies comparing outcomes of foreign tact training with other verbal operant procedures. The preliminary findings indicated foreign tact training produced…

This study examines the special education studies on science education in the ERIC database. The main facts to be determined in the content analysis conducted in this study are as follows: subject types of special education studies in the field of science education, change of preferred studies according to years, main objectives, research methods,…

Background: Meta-analysis refers to the statistical methods employed to combine results of several empirical studies in a topic of interest (Hedges & Olkin, 1985). Meta-analysis is often included in literature review studies to quantitatively analyze data from a collection of studies (Valentine et al., 2010). The statistical power of a…

The purpose of the study is to systematically review studies investigating the script fading procedure on individuals with autism and also determine the quality of the studies and the effect size related to the calculations of the percentage of nonoverlapping data (PND) and the percentage of data exceeding the median (PEM) in the studies. The…

People with disabilities develop skills associated with self-determined action when supports and opportunities, aligned to their strengths and values, are provided in the environments in which they live, learn, and work. Researchers have suggested that a complex array of contextual factors impacts how people with disabilities and their key…

In the era of the "reproducibility crisis" and the "P-value controversy" new ways of presentation and interpretation of the results of a meta-analysis are desirable. One suggestion that has been made for single studies almost six decades ago and taken up now and then is the P-value function. For a given outcome, this function…

Introduction: Interrupted Time Series (ITS) studies may be used to assess the impact of an interruption, such as an intervention or exposure. The data from such studies are particularly amenable to visual display and, when clearly depicted, can readily show the short- and long-term impact of an interruption. Further, well-constructed graphs allow…

Diagnostic test accuracy (DTA) systematic reviews are conducted to summarize evidence on the accuracy of a diagnostic test including a critical evaluation of the primary studies. Where appropriate, the evidence is meta-analyzed to obtain pooled estimates of effectiveness. In this study, we reviewed and critiqued three DTA guidance documents with…

Statistical methods are increasingly being used to integrate findings from the ever-expanding universe of empirical research. Meta-analysis encompasses various techniques for synthesizing summary statistics, and mega-analysis pools raw data across studies. This paper offers an introduction to meta-analysis and mega-analysis that complements the…

Systematic reviews with meta-analyses are powerful tools that can answer research questions based on data from published studies. Ideally, all relevant data is directly available in the text or tables, but often it is only presented in graphs. In those cases, the data can be extracted from graphs, but this potentially introduces errors. Here, we…

Network meta-analysis (NMA) is a statistical technique for the comparison of treatment options. Outcomes of Bayesian NMA include estimates of treatment effects, and the probabilities that each treatment is ranked best, second best and so on. How exactly network topology affects the accuracy and precision of these outcomes is not fully understood.…

Methods for indirect comparisons and network meta-analysis use aggregate level data from multiple studies. A very common, and closely related, scenario is where a company has individual patient data (IPD) from its own trial, but only has published aggregate data from a competitor's trial, and an indirect comparison of the treatments evaluated in…

Content-based techniques for credibility assessment (Criteria-Based Content Analysis [CBCA], Reality Monitoring [RM]) have been shown to distinguish between experience-based and fabricated statements in previous meta-analyses. New simulations raised the question whether these results are reliable revealing that using meta-analytic methods on…

A reference interval provides a basis for physicians to determine whether a measurement is typical of a healthy individual. It can be interpreted as a prediction interval for a new individual from the overall population. However, a reference interval based on a single study may not be representative of the broader population. Meta-analysis can…