Read by QxMD icon Read

Research Synthesis Methods

Nazila Alinaghi, W Robert Reed
This paper studies the performance of the FAT-PET-PEESE (FPP) procedure, a commonly employed approach for addressing publication bias in the economics and business meta-analysis literature. The FPP procedure is generally used for three purposes: (i) to test whether a sample of estimates suffers from publication bias, (ii) to test whether the estimates indicate that the effect of interest is statistically different from zero, and (iii) to obtain an estimate of the mean true effect. Our findings indicate that the FPP procedure performs well in the basic but unrealistic environment of "fixed effects", where all estimates are assumed to derive from a single population value and sampling error is the only reason for why studies produce different estimates...
March 12, 2018: Research Synthesis Methods
Ralf Bender, Tim Friede, Armin Koch, Oliver Kuss, Peter Schlattmann, Guido Schwarzer, Guido Skipka
In systematic reviews meta-analyses are routinely applied to summarize the results of the relevant studies for a specific research question. If one can assume that in all studies the same true effect is estimated, the application of a meta-analysis with common effect (commonly referred to as fixed-effect meta-analysis) is adequate. If between-study heterogeneity is expected to be present, the method of choice is a meta-analysis with random effects. The widely used DerSimonian and Laird method for meta-analyses with random effects has been criticized due to its unfavorable statistical properties, especially in the case of very few studies...
March 5, 2018: Research Synthesis Methods
O O Babatunde, V Tan, J L Jordan, K Dziedzic, C A Chew-Graham, C Jinks, J Protheroe, D A van der Windt
BACKGROUND & AIMS: Barriers to dissemination and engagement with evidence pose a threat to implementing evidence-based medicine. Understanding, retention and recall can be enhanced by visual presentation of information. The aim of this exploratory research was to develop and evaluate the accessibility and acceptability of visual summaries for presenting evidence syntheses with multiple exposures or outcomes to professional and lay audiences. METHODS: 'Evidence flowers' were developed as a visual method of presenting data from four case scenarios: two complex evidence syntheses with multiple outcomes, Cochrane reviews and clinical guidelines...
February 13, 2018: Research Synthesis Methods
Lifeng Lin, Haitao Chu
In medical sciences, a disease condition is typically associated with multiple risk and protective factors. Although many studies report results of multiple factors, nearly all meta-analyses separately synthesize the association between each factor and the disease condition of interest. The collected studies usually report different subsets of factors, and the results from separate analyses on multiple factors may not be comparable because each analysis may use different subpopulation. This may impact on selecting most important factors to design a multi-factor intervention program...
February 9, 2018: Research Synthesis Methods
Jaana Isojarvi, Hannah Wood, Carol Lefebvre, Julie Glanville
Clinical trial data are essential for assessments of the effectiveness of healthcare interventions. Information about ongoing or completed, but not yet formally published, trials has been more difficult to identify until the development of clinical trials registers and portals. This paper summarises research evidence on identifying sources of trial data, how and when to search those sources and which future developments may enhance access to and retrieval of unpublished trial evidence. We conducted a literature search for relevant studies and provide a narrative review of the evidence from these studies...
February 7, 2018: Research Synthesis Methods
Sarah Donegan, Sofia Dias, Catrin Tudur-Smith, Valeria Marinho, Nicky J Welton
BACKGROUND: Meta-regression results must be interpreted taking into account the range of covariate values of the contributing studies. Results based on interpolation or extrapolation may be unreliable. In network meta-regression (NMR) models, which include covariates in network meta-analyses, results are estimated using direct and indirect evidence, therefore it may be unclear which studies and covariate values contribute to which result. We propose graphs to help understand which trials and covariate values contribute to each NMR result and to highlight extrapolation or interpolation...
January 26, 2018: Research Synthesis Methods
Ani Movsisyan, Jane Dennis, Eva Rehfuess, Sean Grant, Paul Montgomery
INTRODUCTION: Rating the quality of a body of evidence is an increasingly common component of research syntheses on intervention effectiveness. This study sought to identify and examine existing systems for rating the quality of a body of evidence on the effectiveness of health and social interventions. METHODS: We used a multi-component search strategy to search for full-length reports of systems for rating the quality of a body of evidence on the effectiveness of health and social interventions published in English from 1995 onward...
January 18, 2018: Research Synthesis Methods
Hannah Wood, Annette O'Connor, Jan Sargeant, Julie Glanville
INTRODUCTION: Systematic review methods are now being used for reviews of food production, food safety and security, plant health, and animal health and welfare. Information retrieval methods in this context have been informed by human health-care approaches and ideally should be based on relevant research and experience. OBJECTIVE: This narrative review seeks to identify and summarize current research-based evidence and experience on information retrieval for systematic reviews in food and feed topics...
January 9, 2018: Research Synthesis Methods
Iain Marshall, Anna Noel Storr, Joël Kuiper, James Thomas, Byron C Wallace
Machine learning (ML) algorithms have proven highly accurate for identifying Randomized Controlled Trials (RCTs), but are not used much in practice, in part because the best way to make use of the technology in a typical workflow is unclear. In this work we evaluate ML models for RCT classification (Support Vector Machines [SVMs], Convolutional Neural Networks [CNNs], and ensemble approaches). We trained and optimised SVM and CNN models on the titles and abstracts of the Cochrane Crowd RCT set. We evaluated the models on an external dataset (Clinical Hedges), allowing direct comparison with traditional database search filters...
January 4, 2018: Research Synthesis Methods
Xin Victoria Wang, Bernard Cole, Marco Bonetti, Richard D Gelbera
We recently developed a method called Meta-STEPP [1] based on the fixed-effects meta-analytic approach to explore treatment effect heterogeneity across a continuous covariate for individual time-to-event data arising from multiple clinical trials. Meta-STEPP forms overlapping subpopulation windows (meta-windows) along a continuous covariate of interest, estimates the overall treatment effect in each meta-window using standard fixed-effects method, plots them against the continuous covariate, and tests for treatment-effect heterogeneity across the range of covariate values...
December 27, 2017: Research Synthesis Methods
Gerta Rücker, Guido Schwarzer
Network meta-analysis has evolved into a core method for evidence synthesis in health care. In network meta-analysis, 3 or more treatments for a given medical condition are compared, based on a number of clinical studies, usually randomized controlled trials. Often, many different endpoints are investigated, related to different aspects of the patient's outcome, such as efficacy, safety, acceptability, or costs of a treatment. Different outcomes may lead to different rankings of the treatments. We use the existing theory of partially ordered sets and show how the relations between the treatments in a network meta-analysis can be illustrated by Hasse diagrams, that is, directed graphs showing the partial order relations, and by structured scatter plots and biplots...
December 2017: Research Synthesis Methods
Loukia M Spineli
OBJECTIVES: Tο report challenges encountered during the extraction process from Cochrane reviews in mental health and Campbell reviews and to indicate their implications on the empirical performance of different methods to handle missingness. METHODS: We used a collection of meta-analyses on binary outcomes collated from a previous work on missing outcome data. To evaluate the accuracy of their extraction, we developed specific criteria pertaining to the reporting of missing outcome data in systematic reviews...
December 2017: Research Synthesis Methods
Adam R Hafdahl
This seventh installment of "Article Alerts" includes a print component with 200 methodological articles about research synthesis published in 2012. More than 800 dissertations and theses have been added to the archive component since the preceding installment. Also since that installment, the parent compilation from which the print and archive components are built has more than doubled and now contains nearly 26 000 items.
December 2017: Research Synthesis Methods
Su Golder, Kath Wright, Yoon K Loke
Authors and indexers are increasingly including terms for adverse drug effects in the titles, abstracts, or indexing of records in MEDLINE and Embase. However, it is not clear if this is the same for studies with nondrug adverse effects data. We therefore assessed the feasibility of using adverse effects terms when searching MEDLINE or Embase to retrieve papers of nondrug adverse effects. A collection of papers that reported data on nondrug adverse effects was sought from included studies of systematic reviews...
December 2017: Research Synthesis Methods
Tracey Carr, Elizabeth Quinlan, Susan Robertson, Angie Gerrard
Realist synthesis techniques can be used to assess complex interventions by extracting and synthesizing configurations of contexts, mechanisms, and outcomes found in the literature. Our novel and multi-pronged approach to the realist synthesis of workplace harassment interventions describes our pursuit of theory to link macro and program level theories. After discovering the limitations of a dogmatic approach to realist synthesis, we adapted our search strategy and focused our analysis on a subset of data. We tailored our realist synthesis to understand how, why, and under what circumstances workplace harassment interventions are effective...
December 2017: Research Synthesis Methods
Robert Suurmond, Henk van Rhee, Tony Hak
We present a new tool for meta-analysis, Meta-Essentials, which is free of charge and easy to use. In this paper, we introduce the tool and compare its features to other tools for meta-analysis. We also provide detailed information on the validation of the tool. Although free of charge and simple, Meta-Essentials automatically calculates effect sizes from a wide range of statistics and can be used for a wide range of meta-analysis applications, including subgroup analysis, moderator analysis, and publication bias analyses...
December 2017: Research Synthesis Methods
Gerta Rücker, Christopher J Cates, Guido Schwarzer
Systematic reviewers conducting pairwise meta-analyses sometimes encounter multi-arm studies. To include these studies, and to avoid a unit-of-analysis error, often two or more arms are combined or the control arm is split. In this tutorial, we present 5 different approaches that can be used. Particularly, we present a novel approach (method 4) that to the best of our knowledge has not been presented before. We demonstrate their application on 3 selected data sets, discuss their scope of application and their advantages and limitations, and give recommendations...
December 2017: Research Synthesis Methods
Suzanne C Freeman, James R Carpenter
Network meta-analysis (NMA) combines direct and indirect evidence from trials to calculate and rank treatment estimates. While modelling approaches for continuous and binary outcomes are relatively well developed, less work has been done with time-to-event outcomes. Such outcomes are usually analysed using Cox proportional hazard (PH) models. However, in oncology with longer follow-up time, and time-dependent effects of targeted treatments, this may no longer be appropriate. Network meta-analysis conducted in the Bayesian setting has been increasing in popularity...
December 2017: Research Synthesis Methods
Audrey Béliveau, Sarah Goring, Robert W Platt, Paul Gustafson
In network meta-analysis, the use of fixed baseline treatment effects (a priori independent) in a contrast-based approach is regularly preferred to the use of random baseline treatment effects (a priori dependent). That is because, often, there is not a need to model baseline treatment effects, which carry the risk of model misspecification. However, in disconnected networks, fixed baseline treatment effects do not work (unless extra assumptions are made), as there is not enough information in the data to update the prior distribution on the contrasts between disconnected treatments...
December 2017: Research Synthesis Methods
Sarah Donegan, Nicky J Welton, Catrin Tudur Smith, Umberto D'Alessandro, Sofia Dias
BACKGROUND: Many reviews aim to compare numerous treatments and report results stratified by subgroups (eg, by disease severity). In such cases, a network meta-analysis model including treatment by covariate interactions can estimate the relative effects of all treatment pairings for each subgroup of patients. Two key assumptions underlie such models: consistency of treatment effects and consistency of the regression coefficients for the interactions. Consistency may differ depending on the covariate value at which consistency is assessed...
December 2017: Research Synthesis Methods
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"