Table 2 Characteristics of stage I descriptive studies
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 | ✓ | ✓ | ✓ | ✓ |
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 | ✓✓ | ✓✓ | ✓✓ | ✓✓ |
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 | ✓✓ | ✓✓ | ✓✓ | |