First Steps in Beginning a Meta-analysis

2013 ◽  
Author(s):  
Gavin B. Stewart ◽  
Isabelle M. Côté ◽  
Hannah R. Rothstein ◽  
Peter S. Curtis
Keyword(s):  
Field Experiment ◽  
Systematic Approach ◽  
Sampling Error ◽  
Meta Analysis ◽  
Research Synthesis ◽  
Systematic Research ◽  
Different Types ◽  
Statistical Approaches ◽  
Definition Of ◽  
Meta Analyses

This chapter discusses the initiation of the process of systematic research synthesis. Without a systematic approach to defining, obtaining, and collating data, meta-analyses may yield precise but erroneous results, with different types of sampling error (biases) and excess subjectivity in choice of methods and definition of thresholds; these devalue the rigor of any statistical approaches employed. The chapter considers exactly the same issues that face an ecologist designing a field experiment. What's the question? How can I define my sampling universe? How should I collect my data? What analyses should I undertake? How should I interpret my results robustly? These questions are considered in the context of research synthesis.

scholarly journals A Statistical Method for Synthesizing Meta-Analyses

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Liansheng Larry Tang ◽  
Michael Caudy ◽  
Faye Taxman
Keyword(s):  
Statistical Method ◽  
Effect Size ◽  
Meta Analysis ◽  
Effect Sizes ◽  
Weighted Mean ◽  
Summary Effect ◽  
Different Types ◽  
Meta Analyses ◽  
Size Estimates ◽  
Similar Search

Multiple meta-analyses may use similar search criteria and focus on the same topic of interest, but they may yield different or sometimes discordant results. The lack of statistical methods for synthesizing these findings makes it challenging to properly interpret the results from multiple meta-analyses, especially when their results are conflicting. In this paper, we first introduce a method to synthesize the meta-analytic results when multiple meta-analyses use the same type of summary effect estimates. When meta-analyses use different types of effect sizes, the meta-analysis results cannot be directly combined. We propose a two-step frequentist procedure to first convert the effect size estimates to the same metric and then summarize them with a weighted mean estimate. Our proposed method offers several advantages over existing methods by Hemming et al. (2012). First, different types of summary effect sizes are considered. Second, our method provides the same overall effect size as conducting a meta-analysis on all individual studies from multiple meta-analyses. We illustrate the application of the proposed methods in two examples and discuss their implications for the field of meta-analysis.

scholarly journals An individual participant data (IPD) meta-analysis on the attachment network to multiple caregivers

2020 ◽  
Author(s):  
Or Dagan ◽  
Pasco Fearon ◽  
Carlo Schuengel ◽  
Marije Verhage ◽  
Glenn I. Roisman ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Developmental Outcomes ◽  
Research Synthesis ◽  
Individual Participant Data ◽  
Attachment Relationship ◽  
Attachment Research ◽  
Individual Participant ◽  
The Subject ◽  
Meta Analyses

Since the seminal 1992 paper by van IJzendoorn, Sagi, and Lambermon, putting forward the “The multiple caretaker paradox”, relatively little attention has been given to the potential joint effects of the role early attachment network to mother and father play in development. Recently, Dagan and Sagi-Schwartz (2018) have published a paper that attempts to revive this unsettled issue, calling for research on the subject and offering a framework for posing attachment network hypotheses. This Collaboration for Attachment Research Synthesis project attempts to use an Individual Participant Data meta-analyses to test the hypotheses put forward in Dagan and Sagi-Schwartz (2018). Specifically, we test (a) whether the number of secure attachments (0,1, or 2) matter in predicting a range of developmental outcomes, and (b) whether the quality of attachment relationship with one parent contributes more than the other to these outcomes.

Transparency of reporting in CALL meta-analyses between 2003 and 2015

ReCALL ◽  
2017 ◽  
Vol 30 (3) ◽  
pp. 253-277 ◽  
Author(s):  
Huifen Lin ◽  
Tsuiping Chen ◽  
Hsien-Chin Liou
Keyword(s):  
Language Learning ◽  
Meta Analysis ◽  
Empirical Studies ◽  
Research Synthesis ◽  
Computer Assisted ◽  
Computer Assisted Language Learning ◽  
Conducting Research ◽  
Number Of Publications ◽  
Meta Analyses ◽  
Research Domain

AbstractSince its introduction by Glass in the 1970s, meta-analysis has become a widely accepted and the most preferred approach to conducting research synthesis. Overcoming the weaknesses commonly associated with traditional narrative review and vote counting, meta-analysis is a statistical method of systematically aggregating and analyzing empirical studies by following well-established procedures. The findings of a meta-analysis, when appropriately conducted, are able to inform important policy decisions and provide practical pedagogical suggestions. With the growing number of publications employing meta-analysis across a wide variety of disciplines, it has received criticism due to its inconsistent findings derived from multiple meta-analyses in the same research domain. These inconsistencies have arisen partly due to the alternatives available to meta-analysts in each major meta-analytic procedure. Researchers have therefore recommended transparent reporting on the decision-making for every essential judgment call so that the results across multiple meta-analyses become replicable, consistent, and interpretable. This research explored the degree to which meta-analyses in the computer-assisted language learning (CALL) discipline transparently reported their decisions in every critical step. To achieve this aim, we retrieved 15 eligible meta-analyses in CALL published between 2003 and 2015. Features of these meta-analyses were extracted based on a codebook modified from Cooper (2003) and Aytug, Rothstein, Zhou and Kern (2012). A transparency score of reporting was then calculated to examine the degree to which these meta-analyses are compliant with the norms of reporting as recommended in the literature. We then discuss the strengths and weaknesses of the methodologies and provide suggestions for conducting quality meta-analyses in this domain.

scholarly journals Comparison of different approaches to antibiotic restriction in food-producing animals: stratified results from a systematic review and meta-analysis

2019 ◽  
Vol 4 (4) ◽  
pp. e001710 ◽  
Author(s):  
Karen L Tang ◽  
Niamh P Caffrey ◽  
Diego B Nóbrega ◽  
Susan C Cork ◽  
Paul E Ronksley ◽  
...  
Keyword(s):  
Systematic Review ◽  
Antibiotic Resistance ◽  
Meta Analysis ◽  
Antibiotic Use ◽  
Growth Promoter ◽  
Antibiotic Resistant ◽  
Random Effects Models ◽  
Differential Effectiveness ◽  
Different Types ◽  
Meta Analyses

BackgroundWe have previously reported, in a systematic review of 181 studies, that restriction of antibiotic use in food-producing animals is associated with a reduction in antibiotic-resistant bacterial isolates. While informative, that report did not concretely specify whether different types of restriction are associated with differential effectiveness in reducing resistance. We undertook a sub-analysis of the systematic review to address this question.MethodsWe created a classification scheme of different approaches to antibiotic restriction: (1) complete restriction; (2) single antibiotic-class restriction; (3) single antibiotic restriction; (4) all non-therapeutic use restriction; (5) growth promoter and prophylaxis restriction; (6) growth promoter restriction and (7) other/undetermined. All studies in the original systematic review that were amenable to meta-analysis were included into this substudy and coded by intervention type. Meta-analyses were conducted using random effects models, stratified by intervention type.ResultsA total of 127 studies were included. The most frequently studied intervention type was complete restriction (n=51), followed by restriction of non-therapeutic (n=33) and growth promoter (n=19) indications. None examined growth promoter and prophylaxis restrictions together. Three and seven studies examined single antibiotic-class and single antibiotic restrictions, respectively; these two intervention types were not significantly associated with reductions in antibiotic resistance. Though complete restrictions were associated with a 15% reduction in antibiotic resistance, less prohibitive approaches also demonstrated reduction in antibiotic resistance of 9%–30%.ConclusionBroad interventions that restrict global antibiotic use appear to be more effective in reducing antibiotic resistance compared with restrictions that narrowly target one specific antibiotic or antibiotic class. Importantly, interventions that allow for therapeutic antibiotic use appear similarly effective compared with those that restrict all uses of antibiotics, suggesting that complete bans are not necessary. These findings directly inform the creation of specific policies to restrict antibiotic use in food-producing animals.

Meta-analysis: A 12-step program

2003 ◽  
Author(s):  
L. Streiner David
Keyword(s):  
Meta Analysis ◽  
Effect Sizes ◽  
Prevalence Rates ◽  
Global Estimate ◽  
Different Types ◽  
Comprehensive Search ◽  
Meta Analyses ◽  
Explicit Criteria ◽  
Step Program

Meta-analysis is a technique for combining the results of many studies in a rigorous and systematic manner, to allow us to better assess prevalence rates for different types of gambling and determine which interventions have the best evidence regarding their effectiveness and efficacy. Meta-analysis consists of (a) a comprehensive search for all available evidence; (b) the use of applying explicit criteria for determining which articles to include; (c) determination of an effect size for each study; and (d) the pooling of effect sizes across studies to end up with a global estimate of the prevalence or the effectiveness of a treatment. This paper begins with a discussion of why meta-analyses are useful, followed by a 12-step program for conducting a meta-analysis. This program can be used both by people planning to do such an analysis, as well as by readers of a meta-analysis, to evaluate how well it was carried out.

scholarly journals Exercise versus Metformin to Improve Pregnancy Outcomes among Overweight Pregnant Women: A Systematic Review and Network Meta-Analysis

2021 ◽  
Vol 10 (16) ◽  
pp. 3490
Author(s):  
Carlos Pascual-Morena ◽  
Iván Cavero-Redondo ◽  
Celia Álvarez-Bueno ◽  
Maribel Lucerón-Lucas-Torres ◽  
Gema Sanabria-Martínez ◽  
...  
Keyword(s):  
Aerobic Exercise ◽  
Pregnant Women ◽  
Web Of Science ◽  
Meta Analysis ◽  
Cochrane Library ◽  
Maternal Weight ◽  
Overweight Women ◽  
Randomized Controlled ◽  
Different Types ◽  
Meta Analyses

Being overweight is associated with pregnancy-related disorders such as gestational diabetes mellitus (GDM), hypertensive disorders of pregnancy (HDP), and excessive maternal weight gain (MWG). Exercise and metformin reduce the risk of these disorders. This network meta-analysis (NMA) aims to compare the effect of metformin and different types of exercise (aerobic, resistance and combined) on the risk of GDM, HDP, and MWG among overweight/obese pregnant women. Medline, EMBASE, Web of Science and Cochrane Library were searched from inception to June 2021. Meta-analyses and NMAs were performed. Sixteen randomized controlled trials were included. In the NMA, aerobic exercise showed an effect on GDM (RR = 0.51, 95% CI = 0.26, 0.97), and metformin a reduction in MWG (MWG = −2.93 kg, 95% CI = −4.98, −0.87). No intervention showed any effect on the reduction of HDP. Our study suggests that aerobic exercise may have the greatest effect in reducing the risk of GDM, and perhaps, the MWG. Strategies should be developed to increase adherence to this type of intervention among overweight women without contraindications. Although metformin could reduce MWG, medicalization of pregnancy in healthy women is not justified with the present results. More research is needed on the effect of the intensity and frequency of exercise sessions and the length of interventions.

Meta-Analysis in Health and Risk Messaging

2017 ◽  
Author(s):  
Simon Zebregs ◽  
Gert-Jan de Bruijn
Keyword(s):  
Meta Analysis ◽  
Empirical Studies ◽  
Research Synthesis ◽  
Basic Knowledge ◽  
Inclusion Criteria ◽  
Clear Cut ◽  
Analytical Research ◽  
Meta Analyses ◽  
Quality Assessments ◽  
Selection Of

Meta-analyses are becoming increasingly popular in the field of health and risk communication—meta-analyses allow for more precise estimations of the magnitude of effects and the robustness of those effects across empirical studies in a particular domain. Despite its popularity, most scholars are not trained in the basic methods involved with meta-analyses. There are advantages to meta-analysis in comparison to other forms of research synthesis. An overview of the methods involved in conducting and reporting meta-analytical research is helpful. However, the methods involved with meta-analyses are not as clear-cut as they may first appear. Numerous issues must be considered and various arbitrary decisions are required during the process. These issues and decisions relate to various topics such as inclusion criteria, the selection of sources, quality assessments for eligible studies, and publication bias. Basic knowledge of these issues and decisions is important for interpreting the outcomes of a meta-analysis correctly.

Spin in Abstracts of Systematic Reviews and Meta-Analyses of Melanoma Therapies: A Cross-Sectional Analysis (Preprint)

2021 ◽  
Author(s):  
Ross Nowlin ◽  
Alexis Wirtz ◽  
David Wenger ◽  
Ryan Ottwell ◽  
Courtney Cook ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Reference Group ◽  
Human Subjects ◽  
Meta Analysis ◽  
Acne Vulgaris ◽  
Inclusion Criteria ◽  
Cross Sectional ◽  
Study Characteristics ◽  
Definition Of ◽  
Meta Analyses

BACKGROUND Spin is defined as the misrepresentation of a study’s results, which may lead to misperceptions or misinterpretation of the findings. Spin has previously been found in randomized controlled trials and systematic reviews of acne vulgaris treatments and treatments of various non-dermatological conditions. OBJECTIVE The purpose of this study was to quantify the presence of spin in abstracts of systematic reviews and meta-analyses of melanoma therapies and identify any related secondary characteristics of these articles. METHODS e used a cross-sectional approach on June 2, 2020, to search the MEDLINE and Embase databases from their inception. To meet inclusion criteria, a study was required to be a systematic review or meta-analysis pertaining to the treatment of melanoma in human subjects, and reported in English. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA) definition of systematic reviews and meta-analyses. Data were extracted in a masked, duplicate fashion. We conducted a powered bivariate linear regression and calculated odds ratios for each study characteristic. RESULTS A total of 200 systematic reviews met the inclusion criteria. We identified spin in 38% of the abstracts. The most common type of spin found was type 3, occurring 40 times; the least common was type 2, which was not present in any included abstracts. We found that abstracts pertaining to pharmacologic interventions were 3.84 times more likely to contain spin than the reference group. The likelihood of an article containing spin has decreased annually (AOR: 0.91; 95% CI, 0.84-0.99). No significant correlation between funding source, other study characteristics, and the presence of spin was identified. CONCLUSIONS We have found that spin is fairly common in the abstracts of systematic reviews of melanoma treatments, but is improving.

The Risk of Community-Acquired Enteric Infection in Proton Pump Inhibitor Therapy: Systematic Review and Meta-analysis

2018 ◽  
Vol 52 (7) ◽  
pp. 613-622 ◽  
Author(s):  
Radwan A. Hafiz ◽  
Chia Wong ◽  
Stuart Paynter ◽  
Michael David ◽  
Geeske Peeters
Keyword(s):  
Proton Pump ◽  
Meta Analysis ◽  
Proton Pump Inhibitor Therapy ◽  
Enteric Infection ◽  
Significant Heterogeneity ◽  
Community Settings ◽  
Increased Risk ◽  
Different Types ◽  
Enteric Infections ◽  
Meta Analyses

Background: Previous meta-analyses suggest that users of proton pump inhibitors (PPIs) have a higher risk of developing enteric infections compared with nonusers. These previous meta-analyses have considerable heterogeneity, and it is not clear whether the effect of PPIs is different for different types of microorganisms. Objective: The aim of this study is to update previous meta-analyses, concentrating on enteric infection in community settings and exploring potential sources of heterogeneity. Methods: A systematic search was conducted on electronic databases (all available years until November 2017). PubMed, EMBASE, Cochrane, and Web of Science were searched using specific keywords related to PPI therapy and community-acquired enteric infection. Eligible studies were selected based on prespecified criteria. Results: A total of 9 observational studies evaluating community-acquired enteric infection were eligible, including 12 separate analyses. The meta-analysis showed that PPI users have an increased risk of developing community-acquired enteric infection (pooled odds ratio [OR] = 4.28; 95% CI = 3.01-6.08). There was significant heterogeneity between the studies ( I2 = 85%; P < 0.001), which was partly explained by type of microorganism. The strength of the association was similar for Salmonella (pooled OR = 4.84; 95% CI = 2.75-8.54; I2 = 58.7%; P = 0.064) and Campylobacter (pooled OR = 5.09; 95% CI = 3-8.64; I2 = 81%; P < 0.001) but lower for studies that combined all bacteria (pooled OR = 2.42; 95% CI = 0.96-6.14; I2 = 94.3%; P < 0.001). Conclusion: PPI users have an increased risk of developing community-acquired enteric infections compared with nonusers. The heterogeneity was partially explained by type of microorganism; the association is stronger for Salmonella and Campylobacter than for all bacteria combined.

scholarly journals Scoping review of COVID-19-related systematic reviews and meta-analyses: can we really have confidence in their results?

2021 ◽  
pp. postgradmedj-2020-139392
Author(s):  
Rachel Wurth ◽  
Michelle Hajdenberg ◽  
Francisco J Barrera ◽  
Skand Shekhar ◽  
Caroline E Copacino ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Scoping Review ◽  
Meta Analysis ◽  
Internal Validity ◽  
Reporting Quality ◽  
Measurement Tool ◽  
Literature Search Strategy ◽  
Definition Of ◽  
Meta Analyses

AimThe aim of this study was to systematically appraise the quality of a sample of COVID-19-related systematic reviews (SRs) and discuss internal validity threats affecting the COVID-19 body of evidence.DesignWe conducted a scoping review of the literature. SRs with or without meta-analysis (MA) that evaluated clinical data, outcomes or treatments for patients with COVID-19 were included.Main outcome measuresWe extracted quality characteristics guided by A Measurement Tool to Assess Systematic Reviews-2 to calculate a qualitative score. Complementary evaluation of the most prominent published limitations affecting the COVID-19 body of evidence was performed.ResultsA total of 63 SRs were included. The majority were judged as a critically low methodological quality. Most of the studies were not guided by a pre-established protocol (39, 62%). More than half (39, 62%) failed to address risk of bias when interpreting their results. A comprehensive literature search strategy was reported in most SRs (54, 86%). Appropriate use of statistical methods was evident in nearly all SRs with MAs (39, 95%). Only 16 (33%) studies recognised heterogeneity in the definition of severe COVID-19 as a limitation of the study, and 15 (24%) recognised repeated patient populations as a limitation.ConclusionThe methodological and reporting quality of current COVID-19 SR is far from optimal. In addition, most of the current SRs fail to address relevant threats to their internal validity, including repeated patients and heterogeneity in the definition of severe COVID-19. Adherence to proper study design and peer-review practices must remain to mitigate current limitations.

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