scholarly journals Estimates of Between-Study Heterogeneity for 705 Meta-Analyses Reported in Psychological Bulletin From 1990–2013

2017 ◽  
Vol 5 (1) ◽  
pp. 4 ◽  
Author(s):  
Sara Van Erp ◽  
Josine Verhagen ◽  
Raoul P. P. P. Grasman ◽  
Eric-Jan Wagenmakers
Keyword(s):  
Psychological Bulletin ◽  
Study Heterogeneity ◽  
Meta Analyses

scholarly journals Estimates of Between-Study Heterogeneity for 705 Meta-Analyses Reported in Psychological Bulletin From 1990-2013

2017 ◽  
Author(s):  
Sara van Erp ◽  
Josine Verhagen ◽  
Raoul P P P Grasman ◽  
Eric-Jan Wagenmakers
Keyword(s):  
Monte Carlo ◽  
Prior Distribution ◽  
Open Science ◽  
Effect Sizes ◽  
Psychological Bulletin ◽  
Data Set ◽  
Study Heterogeneity ◽  
Science Framework ◽  
Meta Analyses ◽  
Q Statistic

We present a data set containing 705 between-study heterogeneity estimates as reported in 61 articles published in Psychological Bulletin from 1990-2013. The data set also includes information about the number and type of effect sizes, the Q-statistic, and publication bias. The data set is stored in the Open Science Framework repository and can be used for several purposes: (1) to compare a specific heterogeneity estimate to the distribution of between-study heterogeneity estimates in psychology; (2) to construct an informed prior distribution for the between-study heterogeneity in psychology; (3) to obtain realistic population values for Monte Carlo simulations investigating the performance of meta-analytic methods.

scholarly journals Probiotics in Pediatrics. A Review and Practical Guide

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2176
Author(s):  
Leontien Depoorter ◽  
Yvan Vandenplas
Keyword(s):  
Health Benefit ◽  
Beneficial Effects ◽  
Treatment Regimens ◽  
Clostridioides Difficile ◽  
Nosocomial Diarrhea ◽  
Infectious Gastroenteritis ◽  
Study Heterogeneity ◽  
Probiotic Strains ◽  
Prophylactic Use ◽  
Meta Analyses

The potential benefit of the administration of probiotics in children has been studied in many settings globally. Probiotics products contain viable micro-organisms that confer a health benefit on the host. Beneficial effects of selected probiotic strains for the management or prevention of selected pediatric conditions have been demonstrated. The purpose of this paper is to provide an overview of current available evidence on the efficacy of specific probiotics in selected conditions to guide pediatricians in decision-making on the therapeutic or prophylactic use of probiotic strains in children. Evidence to support the use of certain probiotics in selected pediatric conditions is often available. In addition, the administration of probiotics is associated with a low risk of adverse events and is generally well tolerated. The best documented efficacy of certain probiotics is for treatment of infectious gastroenteritis, and prevention of antibiotic-associated, Clostridioides difficile-associated and nosocomial diarrhea. Unfortunately, due to study heterogeneity and in some cases high risk of bias in published studies, a broad consensus is lacking for specific probiotic strains, doses and treatment regimens for some pediatric indications. The current available evidence thus limits the systematic administration of probiotics. The most recent meta-analyses and reviews highlight the need for more well-designed, properly powered, strain-specific and dedicated-dose response studies.

scholarly journals Validity of observational evidence on putative risk and protective factors: appraisal of 3744 meta-analyses on 57 topics

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Perrine Janiaud ◽  
Arnav Agarwal ◽  
Ioanna Tzoulaki ◽  
Evropi Theodoratou ◽  
Konstantinos K. Tsilidis ◽  
...  
Keyword(s):  
Protective Factors ◽  
Observational Studies ◽  
Prediction Interval ◽  
Statistical Significance ◽  
Median Number ◽  
Small Study ◽  
Study Heterogeneity ◽  
Large Heterogeneity ◽  
Meta Analyses ◽  
No Gold Standard

Abstract Background The validity of observational studies and their meta-analyses is contested. Here, we aimed to appraise thousands of meta-analyses of observational studies using a pre-specified set of quantitative criteria that assess the significance, amount, consistency, and bias of the evidence. We also aimed to compare results from meta-analyses of observational studies against meta-analyses of randomized controlled trials (RCTs) and Mendelian randomization (MR) studies. Methods We retrieved from PubMed (last update, November 19, 2020) umbrella reviews including meta-analyses of observational studies assessing putative risk or protective factors, regardless of the nature of the exposure and health outcome. We extracted information on 7 quantitative criteria that reflect the level of statistical support, the amount of data, the consistency across different studies, and hints pointing to potential bias. These criteria were level of statistical significance (pre-categorized according to 10−6, 0.001, and 0.05 p-value thresholds), sample size, statistical significance for the largest study, 95% prediction intervals, between-study heterogeneity, and the results of tests for small study effects and for excess significance. Results 3744 associations (in 57 umbrella reviews) assessed by a median number of 7 (interquartile range 4 to 11) observational studies were eligible. Most associations were statistically significant at P < 0.05 (61.1%, 2289/3744). Only 2.6% of associations had P < 10−6, ≥1000 cases (or ≥20,000 participants for continuous factors), P < 0.05 in the largest study, 95% prediction interval excluding the null, and no large between-study heterogeneity, small study effects, or excess significance. Across the 57 topics, large heterogeneity was observed in the proportion of associations fulfilling various quantitative criteria. The quantitative criteria were mostly independent from one another. Across 62 associations assessed in both RCTs and in observational studies, 37.1% had effect estimates in opposite directions and 43.5% had effect estimates differing beyond chance in the two designs. Across 94 comparisons assessed in both MR and observational studies, such discrepancies occurred in 30.8% and 54.7%, respectively. Conclusions Acknowledging that no gold-standard exists to judge whether an observational association is genuine, statistically significant results are common in observational studies, but they are rarely convincing or corroborated by randomized evidence.

scholarly journals Non-pharmacological treatments for irritable bowel syndrome: study protocol of an umbrella review of systematic review and meta-analyses

BMJ Open ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. e027778 ◽  
Author(s):  
Song Jin ◽  
Yi-Fan Li ◽  
Di Qin ◽  
Dan-Qing Luo ◽  
Hong Guo ◽  
...  
Keyword(s):  
Irritable Bowel Syndrome ◽  
Meta Analysis ◽  
Small Study ◽  
Cochrane Central Register ◽  
Pharmacological Treatments ◽  
Umbrella Review ◽  
Study Heterogeneity ◽  
Ethical Approval ◽  
Irritable Bowel ◽  
Meta Analyses

IntroductionNon-pharmacological treatments are used in the management of irritable bowel syndrome, and their effectiveness has been evaluated in multiple meta-analyses. The robustness of the results in the meta-analyses was not evaluated. We aimed to assess whether there is evidence of diverse biases in the meta-analyses and to identify the treatments without evidence of risk of bias.Methods and analysisWe will search MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science and CINAHL Plus for meta-analyses that evaluate the effectiveness of non-pharmacological treatments. The time of publication will be limited from inception to December 2018. The credibility of the meta-analyses will be evaluated by assessing between-study heterogeneity, small-study effect and excess significance bias. The between-study heterogeneity will be assessed using the Cochrane’s Q test, and the extent of the heterogeneity will be classified using the I2statistics. The existence of a small-study effect in a meta-analysis will be evaluated using the funnel plot method and confirmed by Egger’s test. Excess significance bias will be evaluated by comparing the expected number of clinical studies with positive findings with the observed number.Ethics and disseminationNo formal ethical approval is required since we will use publicly available data. We will disseminate the findings of the umbrella review through publication in a peer-reviewed journal and conference presentations.PROSPERO registration numberCRD42018111516.

Meta-analysis: a critical appraisal of the methodology, benefits and drawbacks

2019 ◽  
Vol 80 (11) ◽  
pp. 636-641 ◽  
Author(s):  
Shahjahan Khan ◽  
Breda Memon ◽  
Muhammed A Memon
Keyword(s):  
Data Transfer ◽  
Meta Analysis ◽  
Summary Statistics ◽  
Level Of Evidence ◽  
Common Effect ◽  
Summary Effect ◽  
Study Heterogeneity ◽  
Decision Making Processes ◽  
Meta Analyses ◽  
Medical Disciplines

Meta-analysis has become an integral part of evidence-based decision-making processes and is being increasingly used in medical and non-medical disciplines. Aggregate data or summary statistics continue to be the mainstay of meta-analysis and are used by many professional societies to support clinical practice guidelines. Meta-analyses synthesize the summary statistics from independent trials by pooling them to estimate the underlying common effect size. The results represent the highest level of evidence but only if the chosen studies are of high quality and the selection criteria are fully satisfied. It is important to address the issues of defining an explicit and relevant question, exhaustively searching for the totality of evidence, meticulous and unbiased data transfer or extraction, assessment of between study heterogeneity and the use of appropriate statistical methods for estimating summary effect measures. This article reviews the methodology, benefits and drawbacks of performing a meta-analysis.

scholarly journals Are Community Gardening and Horticultural Interventions Beneficial for Psychosocial Well-Being? A Meta-Analysis

2020 ◽  
Vol 17 (10) ◽  
pp. 3584
Author(s):  
Giuseppina Spano ◽  
Marina D’Este ◽  
Vincenzo Giannico ◽  
Giuseppe Carrus ◽  
Mario Elia ◽  
...  
Keyword(s):  
Human Health ◽  
Effect Size ◽  
Meta Analysis ◽  
Well Being ◽  
City Management ◽  
Community Gardening ◽  
Quantitative Studies ◽  
Bibliographic Records ◽  
Study Heterogeneity ◽  
Meta Analyses

Recent literature has revealed the positive effect of gardening on human health; however, empirical evidence on the effects of gardening-based programs on psychosocial well-being is scant. This meta-analysis aims to examine the scientific literature on the effect of community gardening or horticultural interventions on a variety of outcomes related to psychosocial well-being, such as social cohesion, networking, social support, and trust. From 383 bibliographic records retrieved (from 1975 to 2019), seven studies with a total of 22 effect sizes were selected on the basis of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Meta-analytic findings on 11 comparisons indicate a positive and moderate effect of horticultural or gardening interventions on psychosocial well-being. Moderation analysis shows a greater effect size in individualistic than collectivistic cultures. A greater effect size was also observed in studies involving community gardening compared to horticultural intervention. Nevertheless, an effect of publication bias and study heterogeneity has been detected. Despite the presence of a large number of qualitative studies on the effect of horticulture/gardening on psychosocial well-being, quantitative studies are lacking. There is a strong need to advance into further high-quality studies on this research topic given that gardening has promising applied implications for human health, the community, and sustainable city management.

scholarly journals Physical activity and cancer: an umbrella review of the literature including 22 major anatomical sites and 770 000 cancer cases

2017 ◽  
Vol 52 (13) ◽  
pp. 826-833 ◽  
Author(s):  
Leandro Fórnias Machado de Rezende ◽  
Thiago Hérick de Sá ◽  
Georgios Markozannes ◽  
Juan Pablo Rey-López ◽  
I-Min Lee ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Physical Activity ◽  
Lower Risk ◽  
Umbrella Review ◽  
Recreational Physical Activity ◽  
Eligibility Criteria ◽  
Protective Association ◽  
Suggestive Evidence ◽  
Study Heterogeneity ◽  
Meta Analyses

ObjectiveTo provide an overview of the breadth and validity of claimed associations between physical activity and risk of developing or dying from cancer.DesignUmbrella review.Data sourcesWe searched Medline, Embase, Cochrane Database and Web of Science.Eligibility criteria for selecting studiesSystematic reviews about physical activity and cancer incidence and cancer mortality in different body sites among general population.ResultsWe included 19 reviews covering 22 cancer sites, 26 exposure-outcome pairs meta-analyses and 541 original studies. Physical activity was associated with lower risk of seven cancer sites (colon, breast, endometrial, lung, oesophageal, pancreas and meningioma). Only colon (a protective association with recreational physical activity) and breast cancer (a protective association with overall physical activity) were supported by strong evidence and highly suggestive evidence, respectively. Evidence from endometrial, lung, oesophageal, pancreas and meningioma presented hints of uncertainty and bias in the literature (eg, not reaching P values<10-6) showing large between-study heterogeneity and/or not demonstrating a definite direction for the effect when 95% prediction intervals were considered. Four of the 26 meta-analyses showed small study effects and 4 showed excess significance.ConclusionPhysical activity is associated with a lower risk of several cancers, but only colon and breast cancer associations were supported by strong or highly suggestive evidence, respectively. Evidence from other cancer sites was less consistent, presenting hints of uncertainty and/or bias.

Assessing publication bias in meta-analyses in the presence of between-study heterogeneity

2010 ◽  
Vol 173 (3) ◽  
pp. 575-591 ◽  
Author(s):  
Jaime L. Peters ◽  
Alex J. Sutton ◽  
David R. Jones ◽  
Keith R. Abrams ◽  
Lesley Rushton ◽  
...  
Keyword(s):  
Publication Bias ◽  
Study Heterogeneity ◽  
Meta Analyses
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