Methodological developments in searching for studies for systematic reviews: past, present and future?

Abstract

The Cochrane Collaboration was established in 1993, following the opening of the UK Cochrane Centre in 1992, at a time when searching for studies for inclusion in systematic reviews was not well-developed. Review authors largely conducted their own searches or depended on medical librarians, who often possessed limited awareness and experience of systematic reviews. Guidance on the conduct and reporting of searches was limited. When work began to identify reports of randomized controlled trials (RCTs) for inclusion in Cochrane Reviews in 1992, there were only approximately 20,000 reports indexed as RCTs in MEDLINE and none indexed as RCTs in Embase. No search filters had been developed with the aim of identifying all RCTs in MEDLINE or other major databases. This presented The Cochrane Collaboration with a considerable challenge in identifying relevant studies.Over time, the number of studies indexed as RCTs in the major databases has grown considerably and the Cochrane Central Register of Controlled Trials (CENTRAL) has become the best single source of published controlled trials, with approximately 700,000 records, including records identified by the Collaboration from Embase and MEDLINE. Search filters for various study types, including systematic reviews and the Cochrane Highly Sensitive Search Strategies for RCTs, have been developed. There have been considerable advances in the evidence base for methodological aspects of information retrieval. The Cochrane Handbook for Systematic Reviews of Interventions now provides detailed guidance on the conduct and reporting of searches. Initiatives across The Cochrane Collaboration to improve the quality inter alia of information retrieval include: the recently introduced Methodological Expectations for Cochrane Intervention Reviews (MECIR) programme, which stipulates 'mandatory’ and 'highly desirable’ standards for various aspects of review conduct and reporting including searching, the development of Standard Training Materials for Cochrane Reviews and work on peer review of electronic search strategies. Almost all Cochrane Review Groups and some Cochrane Centres and Fields now have a Trials Search Co-ordinator responsible for study identification and medical librarians and other information specialists are increasingly experienced in searching for studies for systematic reviews.Prospective registration of clinical trials is increasing and searching trials registers is now mandatory for Cochrane Reviews, where relevant. Portals such as the WHO International Clinical Trials Registry Platform (ICTRP) are likely to become increasingly attractive, given concerns about the number of trials which may not be registered and/or published. The importance of access to information from regulatory and reimbursement agencies is likely to increase. Cross-database searching, gateways or portals and improved access to full-text databases will impact on how searches are conducted and reported, as will services such as Google Scholar, Scopus and Web of Science. Technologies such as te...

Impact of librarians on reporting of the literature searching component of pediatric systematic reviews

“…Many studies have advocated for and described various roles that librarians and information professionals could play on a review team [17][18][19][20][21][22][23][24][25][26]. Several standards and organizations also suggest that a librarian or information professional be involved in the review process [27][28][29][30].…”

Patient healthcare trajectory. An essential monitoring tool: a systematic review

“…Ultimately, they categorised documents according to these annotations. Thus, combining text mining methods for systematic review is a hot topic [72][73][74][75].…”

Systematic reviews: significance of search strategy

“…This process includes searching for grey literature; handsearching of key journals; cited/citing referencing which are known as "snowballing"/"pearl growing" (Glasziou, 2001;Petticrewand Roberts, 2006& Lefebvre et al, 2013.Grey literature is best defined as: "That which is produced on all levels of government, academics, business and industry in print and electronic formats, but which is not controlled by commercial publishers." (Fourth International Conference on Grey Literature, 1999; Haig and Dozier, 2003) With recent developments, revision and implementation of quality improvement measures on standards of methodology of SRs, the quality of information retrieval aspect has become challenging for researchers (Lefebvre et al, 2013). At present, the standards developed by the US Institute of Medicine specifies the requirement of having a librarian/information specialist in the review team (Eden, et al, 2011).…”

“…Opening of the UK Cochrane Center in 1993 and establishment of NHS Center for Reviews and Dissemination in 1994 were among many developments in the UK, to support preparation, maintaining and dissemination of SRs (Chalmers, Hedges, & Cooper, 2002;Petticrewand Roberts, 2006). In 1993 Cochrane Collaboration was established in the USA (Chalmers, Hedges, & Cooper, 2002;Lefebvre, Glanville, Wieland, Coles & Weightman, 2013) with the aim of collecting and summarizing the best evidence from research to help make informed decisions for improved healthcare.…”