250 likes | 258 Views
Learn advanced search techniques using Ovid software, how to read a search strategy, and how to include grey literature in your systematic review. Discover helpful filters and resources for finding relevant studies.
E N D
Systematic Reviews - Part IIKaren Poolekaren.poole@kcl.ac.ukInformation Specialist – School of Biomedical SciencesJohn Galejohn.r.gale@kcl.ac.ukInformation Specialist – Institute of Psychiatry
Introduction • More advanced search techniques using Ovid software • Reading a search strategy • Grey literature: dissertations, conference proceedings, Government reports, unpublished trials etc • Selecting studies to include in your review • Documenting your search • Where to go to get extra help/find out more
An example of a search strategy http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006911.pub2/abstract (navigate to Appendices for search strategy via ‘Jump to’ box under Article tab).
Practical • Truncation – behavio* therapy • Wildcard searching – p?ediatrics • Adjacency searching – acute adj5 otitis media • Boolean operators – AND/OR/NOT • Floating sub-headings • Limiting to fields – PT, TW, AB • Subject headings vs free-text searching
Using Filters • Cochrane filter for RCTs • http://www.cochrane.org/handbook/6411-search-filters • SIGN • http://www.sign.ac.uk/methodology/filters.html • Centre for Reviews and Dissemination • http://www.york.ac.uk/inst/crd/intertasc/rct.htm • National Clinical Guideline Centre • http://www.ncgc.ac.uk/Guidelines/(navigate to appendix of specific guideline) • McMaster University Hedges Project • http://hiru.mcmaster.ca/hiru/HIRU_Hedges_home.aspx
Grey Literature “There are many definitions of grey literature, but it is usually taken to mean literature that is not formally published in sources such as books or journal articles.” (Cochrane Handbook, 2011) Examples of grey literature include: • Technical or research reports from government agencies • Reports from scientific research groups • Working papers from research groups or committees • Doctoral dissertations • Some conference proceedings and official publications
Publication bias Papers with more ‘interesting’ results are more likely to be: • Submitted for publication • Accepted for publication • Published in a major journal • Published in the English language • Publication bias and outcome reporting bias: agomelatine as a case example. Howland, R. H. Journal of Psychoscocial Nursing and Mental Health Services 49(9), September 2011
Searching grey literature • openGrey (System for Information on Grey Literature) http://www.opengrey.eu/ • HMIC (The Healthcare Management Information Consortium) – DH and King’s Fund – via Databases list on OneSpace (King’s username and password) • The National Technical Information Service (NTIS) US and non-US government-sponsored research www.ntis.gov/ • Libraries of specialist research organisations and professional societies
Conference Proceedings Need to try and get full-text if possible Can be found on: • Web of Science • Scopus • Zetoc Available on the Library Services database list If full text isn’t available then order through the free inter-library loan service (ILL).
Theses and Dissertations Some databases e.g. CINAHL and PsycInfo include dissertations WorldCat dissertations and Theses (OCLC) can be accessed via OneSpace AND – via Senate House – Index to Theses in Great Britain and Ireland covers >500,000 theses BUT – usually not full text so might need to get them via ILL or travel to other libraries
Trials Registers Metaregisters of Controlled Trials – which bring together several international sources • The IFPMA clinical trial portal • The International Standard Randomised Controlled Trial Number (ISRCTN) register • The WHO International Clinical Trials registry • US register of clinical trials • Other resources available in the Cochrane Handbook
Handsearching Physically searching the contents of journals, conference proceedings and abstracts page by page • Can identify articles not yet included in electronic databases • Articles or studies not indexed properly BUT it’s impossible to search all journals so prioritise using the results of your searches of databases such as MEDLINE, EMBASE etc You can also use the reference lists of papers you have found earlier
Direct Contact • Making direct contact – usually by email – with the authors or organisations who are experts in this field • Authors often include their contact details in abstracts • Can find out about ongoing or unpublished research • Papers not on your list which authors might be aware of
Relevant internet resources This does NOT mean Google or Google Scholar! Look at specific relevant websites aimed at a particular topic or subject search engines: • Royal College and Society webpages for reports and guidance • NHS Evidence - http://www.evidence.nhs.uk/ • NHS search engine to locate evidence in health and social care. • TRIP database http://www.tripdatabase.com/ • clinical search tool to identify the highest quality clinical evidence for clinical practice.
Selecting studies and managing references • Merge and de-duplicate search results using bibliographic software (make a copy of de-duped) • Examine title and abstracts • Best practice to retain evidence of what articles have been excluded (and potentially why) • Retrieve full text of potentially relevant articles • Link together multiple reports
How much is enough? • Funding/time • A broad search topic or searching more databases/resources etc all increases the amount of time required to sift results. No set timescale – depends on your circumstances and any funding restrictions • Focusing on RCTs/observational studies • Widening a SR to include observational studies is likely to increase the number of results you have to sift through. • Personal/team knowledge – are all key known papers in your subject area retrieved in the search? • Amend search if not/include further databases – you would expect key papers to be returned by a successful search strategy if indexed in the databases you are searching.
Inclusion/Exclusion Criteria • Randomised Controlled Trials (RCTs) usually seen as the gold standard [e.g. required for Cochrane SRs on interventions if possible] • This not always possible e.g. Interventions on pregnant women • How big was the trial? • Will you only include trials with >5; >10; >50; >100 active participants? • Double-blind? • Compared to placebo, waiting list or another treatment?
Study flow diagrams Flow diagram should present the number of: • unique records identified by the searches • records excluded after preliminary screening (e.g. of titles and abstracts) • records retrieved in full text • records or studies excluded after assessment of full text • studies meeting eligibility criteria for the review • studies contributing to the main outcome • check lists and flow diagrams available from the PRISMA web site (PRISMA, 2009)
Documenting your search This is crucial because: It forms a vital part of the systematic review in its own right Your searches should be able to be evaluated by other researchers and reproduced in the future
Documenting your search 2 What you need to record: Information about the databases and interfaces searched including dates covered and when you did your search Full, detailed search strategies (copied and pasted) and the number of records retrieved Details of other searches including conference proceedings, handsearching, contact with experts, reference lists and citation searching and internet searching You’ll also need to specify the criteria you use to select trials – beyond the scope of this course! There are examples at http://www.york.ac.uk/inst/crd/SysRev/!SSL!/WebHelp/SysRev3.htm
External Resources • CRD’s Guidance for undertaking reviews in healthcare http://www.york.ac.uk/inst/crd/index_guidance.htm • Cochrane Handbook http://www.cochrane-handbook.org/ http://training.cochrane.org/ • Intertasc – www.york.ac.uk/inst/crd/intertasc/ • PRISMA – www.prisma-statement.org • Critical Appraisal Skills Programme http://www.casp-uk.net/
EndNote courses • Keep an eye out on Skills Forge https://training.kcl.ac.uk • 1:1s available with your Information Specialist whose contact details you can find at: http://www.kcl.ac.uk/library/support/spec/specialists.aspx
Further information and support Library Services’ Searching for Literature guide • User guides on specific interfaces and databases available at http://www.kcl.ac.uk/library/help/guides.aspx • Contact your school’s Information Specialist at http://www.kcl.ac.uk/library/contact/spec/specialists.aspx • EndNote pages at http://www.kcl.ac.uk/library/help/bibsoftware/endnote/index.aspx