Basic Steps of a Literature Search
Tutorials from the Yale Medical Library
Executing the Database Search
In this example below, the individual components are searched first, utilizing OR to combine terms 1 and 2. The finalized result set (search #15) is obtained by combining these searches with AND and applying limits. Organization of the search strategy in this manner facilitates evaluation by the systematic review team and provides the reader with a display which is easier to follow in the published article.
The following search example in PubMed utilizing P, I and O components for the research question "In patients with autism, does music therapy improve social interaction." Note that this statement does not include a comparison. Keyword truncation (*) and MeSH terms are both applied to this search. The final search #10 shows that the filters for Clinical Trial and published in the last 5 years resulted in a set of seven citations.
Search Hedges/Filters
Consider using a preconfigured search strategy--also called a hedge or filter--to help retrieve more relevant citations. These sites include hedges for topics such as randomozied controlled trials, qualitative research, age groups, etc. Some also include information on the quality of the hedges: have they been validated? Are they current?
- CADTH Search Filters DatabasePresents an assortment of search filters developed and maintained by CADTH’s Research Information Services Filters Working Group. Filters have been extensively tested by the Research Information Services team and are routinely used in CADTH projects. Some filters have been validated against a gold standard set of articles, while others have been pragmatically validated.
- Clinical Queries (PubMed)Also available in Ovid MEDLINE; click "additional limits".
- Cochrane Highly Sensitive Search Strategies for identifying randomized trials in MEDLINEChapter 4: 4.S1: Supplementary Material: Technical Supplement. Section 3.6.1.
PubMed: Box 3.a (sensitivity-maximizing version) & 3.b (sensitivity- and precision-maximizing version); Ovid: Box 3.c (sensitivity-maximizing version) & 3.d (sensitizing- and precision-maximizing version) - Finding Search Filters for Study Designs: Using the ISSG Search Filter ResourceDiscussion of the site's content and architecture: "Launch" feature; validation studies; links to comments and errata; abstracts; critical appraisals; comparative performance data; publications about search filter performance; notes reflecting filter updates. Guidance on how to cite a filter and selecting the best performing filter.
- ISSG (InterTASC Information Specialists' Sub-Group) Search Filter ResourceA collaborative venture to identify, assess and test search filters designed to retrieve research by study design or focus. The Search Filters Resource aims to provide easy access to published and unpublished search filters.
- McMaster Health Knowledge Refinery: Hedges ProjectThe focus of the Hedges Project is to investigate ways to develop and harness (“hedges”) to improve retrieval of scientifically sound and clinically relevant study reports from large, general purpose, biomedical research bibliographic databases including MEDLINE, EMBASE, and PsycINFO.
Evaluating & Reporting Search Strategies
- PRESS Peer Review of Electronic Search StrategiesThe PRESS guideline provides a set of recommendations concerning the information that should be used by librarians and other information specialists when they are asked to evaluate these electronic search strategies. This guideline updates and expands upon the 2008 CADTH report PRESS Peer Review of Electronic Search Strategies. It should be noted that PRESS focuses on the quality of the Boolean search and is only one aspect of a comprehensive search for SRs and HTAs.
- PRISMA for Searching (PRISMA-Search)Includes Links to Key Documents: Checklist, Statement/Explanatory paper, FAQs paper.
Hand Searching
- A method of searching article-by-article through targeted journals to identify relevant studies that database searching may have missed
- Print journals: a manual page-by-page examination of the entire contents of a journal issue or conference proceedings to identify all eligible reports of trials
- Electronic journals: can also be ‘handsearched’ in a similar manner to that advocated for journals in print form, in that each screen or ‘page’ can be checked for possibly relevant studies in the same way as handsearching a print journal