Meta-analyses are systematic summaries of research that use quantitative methods to find the mean effect size (standardized mean difference) for interventions. Critics of meta-analysis point out that such analyses can conflate the results of low- and high-quality studies, make improper comparisons and result in statistical noise. All these…

Many randomized controlled trials have investigated the role of school-based prevention interventions to reduce symptoms of anxiety and depression in young people. Systematic reviews have subsequently demonstrated a small, beneficial effect of these interventions when compared to a combined control group including usual care, no intervention, or…

During drug development, a biomarker is sometimes identified as separating a patient population into those with more and those with less benefit from evaluated treatments. Consequently, later studies might be targeted, while earlier ones are performed in mixed patient populations. This poses a challenge in evidence synthesis, especially if only…

Randomised trials are often funded by commercial companies and methodological studies support a widely held suspicion that commercial funding may influence trial results and conclusions. However, these studies often have a risk of confounding and reporting bias. The risk of confounding is markedly reduced in meta-epidemiological studies that…

Network meta-analysis is a popular method to synthesize the information obtained in a systematic review of studies (e.g., randomized clinical trials) involving subsets of multiple treatments of interest. The dominant method of analysis employs within-study information on treatment contrasts and integrates this over a network of studies. One…

Many randomized trials evaluate an intervention effect on time-to-event outcomes. Individual participant data (IPD) from such trials can be obtained and combined in a so-called IPD meta-analysis (IPD-MA), to summarize the overall intervention effect. We performed a narrative literature review to provide an overview of methods for conducting an…

Time-course model-based network meta-analysis (MBNMA) has been proposed as a framework to combine treatment comparisons from a network of randomized controlled trials reporting outcomes at multiple time-points. This can explain heterogeneity/inconsistency that arises by pooling studies with different follow-up times and allow inclusion of studies…

Randomized clinical trials underpin evidence-based clinical practice, but flaws in their conduct may lead to biased estimates of intervention effects and hence invalid treatment recommendations. The main approach to the empirical study of bias is to collate a number of meta-analyses and, within each, compare the results of trials with and without…

Many public and private initiatives have focused on improving prekindergarten (PK) through Grade 12 mathematics education, given that the mathematics content learned before college is foundational for later learning and college success across STEM subjects. Although decades of educational research have studied PK-12 mathematics interventions, the…

Objective: Various statistical methods have been developed to estimate hazard ratios (HRs) from published Kaplan-Meier (KM) curves for the purpose of performing meta-analyses. The objective of this study was to determine the reliability, accuracy, and precision of four commonly used methods by Guyot, Williamson, Parmar, and Hoyle and Henley.…

A modification of the first stage of the standard procedure for two-stage meta-analytic structural equation modeling for use with large complex datasets is presented. This modification addresses two common problems that arise in such meta-analyses: (a) primary studies that provide multiple measures of the same construct and (b) the correlation…

Purpose: The purpose of this article is to discuss the current state of interventions for improving working memory (WM) capacity language and academic skills and to provide suggestions for speech-language pathologists working with students who have WM capacity limitations. Method: Meta-analyses, systematic reviews, randomized controlled trials,…

Meta-analyses combine the results of multiple studies of a common question. Approaches based on effect size estimates from each study are generally regarded as the most informative. However, these methods can only be used if comparable effect sizes can be computed from each study, and this may not be the case due to variation in how the studies…

Background: Evidence of treatment foster care (TFC) and group care's (GC) potential to prevent delinquency and crime has been developing. Objectives: We clarified the state of comparative knowledge with a historical overview. Then we explored the hypothesis that smaller, probably better resourced group homes with smaller staff/resident ratios have…

Most evaluators have embraced the goal of evidence-based practice (EBP). Yet, many have criticized EBP review systems that prioritize randomized control trials and use various criteria to limit the studies examined. They suggest this could produce policy recommendations based on small, unrepresentative segments of the literature and recommend a…