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Table 2 Characteristics of stage I descriptive studies

From: Toward a comprehensive evidence map of overview of systematic review methods: paper 1—purpose, eligibility, search and data extraction

    Steps in the conduct of an overview
Citation Type of study Summary description of the article Purpose, objectives, scope Eligibility criteria Search methods Data extraction
Baker 2014 [29]
The benefits and challenges of conducting an overview of systematic reviews in public health: a focus on physical activity.
Article describing methods for overviews • Describes the usefulness of overviews for decision makers and summarises some procedural steps to be undertaken
• Provides a case study of an overview on public health interventions for increasing physical activity
 
Becker 2008 [1]
Overviews of reviews.
Guidance for undertaking overviews • Early guidance providing the structure and procedural steps for the production of an overview
• Details the different purposes of an overview, providing examples and describes how to present findings through tables and figures
Bolland 2014 [30]
A case study of discordant overlapping meta-analyses: vitamin D supplements and fracture.
Article describing methods for overviews • Describes criteria for explaining differences in overlapping M-As with discordant conclusions
• Builds on the guide to interpret discordant SRs proposed by Jadad 1997
• Suggests reporting items there are overlapping trials in M-As
 
Caird 2015 [31]
Mediating policy-relevant evidence at speed: are systematic reviews of systematic reviews a useful approach?
Article describing methods for overviews • Describes the methodological challenges in the production of overviews that mediate existing synthesised knowledge to policy makers
• Describes the trade-offs between producing a rapid overview and its comprehensiveness and reliability
Chen 2014 [2]
Scientific hypotheses can be tested by comparing the effects of one treatment over many diseases in a systematic review.
Study examining methods used in a cohort of overviews • Identifies possible aims of an overview as being to detect unintended effects, improve the precision of effect estimates, or explore heterogeneity of effect across disease groups
• Describes the value and pitfalls of synthesis of M-As using three case studies
  
CMIMG 2012 [4]
Review type and methodological considerations.
Guidance for undertaking overviews • Provides updated Cochrane guidance on the purpose and conduct of overviews
• Builds on the Cochrane guidance for overviews by Becker 2008
• Describes the factors in the decision to conduct an overview vs. an SR
Cooper 2012 [32]
The overview of reviews: unique challenges and opportunities when research syntheses are the principal elements of new integrative scholarship.
Article describing methods for overviews • Describes steps in the conduct of an overview and methods to address challenges (for example dealing with overlap in primary studies)
• Describes methods for second order meta-analysis
Flodgren 2011 [33]
Challenges facing reviewers preparing overviews of reviews.a
Article describing methods for overviews • Mentions the issue of missing or inadequately reported data
• Mentions the challenges in summarising and evaluating large amounts of heterogeneous data
   
Foisy 2011 [34]
Mixing with the ‘unclean’: Including non-Cochrane reviews alongside Cochrane reviews in overviews of reviews.a
Article describing methods for overviews • Describes some challenges inherent in the eligibility criteria process (defining AMSTAR scoring as inclusion criteria, inclusion of non-Cochrane reviews alongside Cochrane reviews)
• Develops inclusion criteria to minimise overlap in primary studies
   
Hartling 2012 [35]
A descriptive analysis of overviews of reviews published between 2000 and 2011.
Study examining methods used in a cohort of overviews • Describes steps in the conduct of overviews and methods used
• Describes methodological standards for SRs (MECIR) and their applicability to overviews
• Describes PRISMA reporting standards and their applicability to overviews
Hartling 2013 [36]
Generating empirical evidence to support methods for overviews of reviews.a
Study examining methods used in a cohort of overviews • Mentions challenges relating to the eligibility criteria process in terms of SR quality, search dates, the strength of the evidence to include, etc.   
Hartling 2014 [37]
Systematic reviews, overviews of reviews and comparative effectiveness reviews: a discussion of approaches to knowledge synthesis.
Article describing methods for overviews • Briefly defines overviews, mentions the purposes in conducting an overview, and discusses some methodological challenges    
Ioannidis 2009 [38]
Integration of evidence from multiple meta-analyses: a primer on umbrella reviews, treatment networks and multiple treatments meta-analyses.
Article describing methods for overviews • Defines umbrella reviews as a pre-step to network meta-analysis
• Describes challenges of overviews and a checklist of pitfalls
   
James 2014 [39]
Informing the methods for public health overview reviews: a descriptive analysis of Cochrane and non-Cochrane public health overviews.a
Study examining methods used in a cohort of overviews • Briefly describes several steps in the conduct of overviews including determining the eligibility criteria and search methods
• Compares Cochrane and non-Cochrane reviews in terms of restrictions on inclusion criteria
 
Joanna Briggs Institute (JBI) 2014 [40, 41]
Methodology for JBI umbrella reviews.
Guidance for undertaking overviews • Provides guidance as to what methods should be used at which step in the conduct of an overview
• Provides stylistic conventions for overviews to meet publication and reporting criteria for the JBI Database of Systematic Reviews and Implementation Reports
Kovacs 2014 [42]
Overviews should meet the methodological standards of systematic reviews.
Commentary or editorial that discuss methods for overviews • Mentions four methodological shortcomings of one overview on surgical interventions as a letter to the editor    
Kramer 2009 [43]
Preparing an overview of reviews: lessons learned.a
Article describing methods for overviews • Mentions the challenges encountered when the authors conducted three overviews including missing information when extracting data    
Li 2012 [44]
Quality and transparency of overviews of systematic reviews.
Article describing methods for overviews • Presents a pilot reporting/quality checklist
• Evaluates a cohort of overviews using the pilot tool, with the mean number of items but no details of the items
Pieper 2012 [6, 45]
Overviews of reviews often have limited rigor: a systematic review.
Study examining methods used in a cohort of overviews • Describes the methods used in a cohort of overviews
• Recommends using validated search filters for retrieval of SRs
• Discusses whether to update the overview by including primary studies published after the most recent SR
Pieper 2014 [46]
Methodological approaches in conducting overviews: current state in HTA agencies.
Article describing methods for overviews • Describes the methods recommended in 8 HTA guideline documents related to overviews
• Compares the Cochrane Handbook guidance to guidance produced by HTA agencies
   
Pieper 2014 [47]
Up-to-dateness of reviews is often neglected in overviews: a systematic review.
Study examining methods used in a cohort of overviews • Describes the process of searching for primary studies in an overview
• Presents decision rules for when to search for primary studies
• Outlines search methods in terms of sequential versus parallel searching for SRs and primary studies
    
Robinson 2016 [48,49,50,51,52]
Integrating bodies of evidence: existing systematic reviews and primary studies.
Article describing methods for overviews • Describes the steps to undertake a complex review that includes multiple SRs, which is similar to overviews
• Discusses challenges inherent in the production of complex reviews that include SRs
Ryan 2005 [53, 54]
Building blocks for meta-synthesis: data integration tables for summarising, mapping, and synthesising evidence on interventions for communicating with health consumers.
Article describing methods for overviews • Presents tabular methods to deal with the preparation of overview evidence
• Discusses the data extraction process and organisation of data
• Presents a table of taxonomy of outcomes from the included SRs, and a data extraction table based on this taxonomy
  
Salanti 2011 [3]
Evolution of Cochrane intervention reviews and overviews of reviews to better accommodate comparisons among multiple interventions.
Guidance for undertaking overviews • Provides Cochrane guidance on the definition of an overviews and as compared to SRs
• Suggests broadening the search in an overview to include individual studies
• Suggests missing data should be retrieved from original reports
Silva 2015 [55]
Overview of systematic reviews - a new type of study.
Study examining methods used in a cohort of overviews • Examines a cohort of Cochrane reviews for methods used
• Documented the sources and types of search strategies conducted
    
Singh 2012 [56]
Development of the Metareview Assessment of Reporting Quality (MARQ) Checklist.
Article describing methods for overviews • Presents a pilot reporting/quality checklist
• Evaluates four case studies using the pilot tool, with the mean number of items but no details of the items
   
Smith 2011 [57]
Methodology in conducting a systematic review of systematic reviews of healthcare interventions.
Article describing methods for overviews • Describes some steps and challenges in undertaking an overview, namely search methods, study selection, quality assessment, and presentation of results
• Presents tabular methods for the preparation of an overview
Thomson 2010 [58]
The evolution of a new publication type: Steps and challenges of producing overviews of reviews.
Article describing methods for overviews • Describes some steps in undertaking an overview and the challenges inherent in production of overviews
• Discusses that gaps or lack of currency in included evidence will weaken the overview findings
  
Thomson 2013 [59]
Overview of reviews in child health: evidence synthesis and the knowledge base for a specific population.
Study examining methods used in a cohort of overviews • Describes the process of including trials in overviews
▪ Discusses the challenge of overview topics differing from the topics of the included SRs
▪ Provides potential solutions as to what to do when mixed populations are reported in SRs and how to extract age subgroup data
 
  1. AMSTAR A MeaSurement Tool to Assess systematic Reviews, CMIMG Comparing Multiple Interventions Methods Group, JBI Joanna Briggs Institute, PRISMA Preferred Reporting Items for Systematic reviews and Meta-Analyses, HTA health technology assessment, MECIR Methodological Expectations of Cochrane Intervention Reviews, SR systematic review, M-As meta-analyses
  2. aIndicates a poster presentation
  3. Indicates a study describing one or more methods
  4. Indicates a study mentioning one or more methods