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Exhaustive Literature Searching (Systematic Reviews)


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Details the search component of systematic review projects.

Published in: Science
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Exhaustive Literature Searching (Systematic Reviews)

  2. 2. Overview  Search construction  Sources  PubMed, OVID MEDLINE, EMBASE, etc.  Reporting
  3. 3. From: Users’ Guide to the Medical Literature (JAMA Evidence)
  4. 4. Evidence Pyramid
  5. 5. Why search?  A high-quality lit search is essential for a successful meta-analysis  It is from the search results that data is gathered for analysis  Failure to locate important studies can significantly affect results  Remember the goal is to capture every relevant study  Important to report search so your methodology can be reproduced
  6. 6. What to expect?  Expect 1000s of results  Expect to search multiple databases  Ovid, EMBASE, PubMed, Scopus, etc.  Expect the search process to take awhile  Expect to publish search strategy and search methodology  Expect to consult a professional with search expertise (health sciences librarian)
  7. 7. Search construction  Concept building  Boolean logic  Vocabulary  Techniques  Evaluating searches
  8. 8. Search construction: Concept building  Identify major concepts of topic  PICO helps for clinical questions, but the concept can be applied in other contexts  Example: Do any olfactory identification tests predict the development of Alzheimer’s disease? ]   What are the major concepts?  Alzheimer disease  Olfactory tests  Predict?  People/Humans?
  9. 9. Search construction: Concept building  Alternate words / Synonyms  Alzheimer, Alzheimer’s, dementia, cognition disorders  Olfactory tests, sniffin’ sticks, b-sit, cc sit, smell identification test
  10. 10. Search construction: Boolean Logic  AND Alzheimer’ s Disease Olfactory test Alzheimer’ Dementia s disease Humans Animals  OR  NOT
  11. 11. Search construction: Boolean Logic Concept 2 Concept 1 Alzheimer disease OR AND dementia Olfactory Identification test OR B-sit OR Sniffin’ Sticks OR Etc. (alzheimer disease OR dementia) AND (olfactory identification test OR b-sit OR sniffin’ sticks OR …)
  12. 12. Search construction: Vocabulary Keywords Controlled vocabularies
  13. 13. Search construction: Vocabulary Keywords Controlled vocabularies What are they?  Literal search  Looks for occurrences of words When to use?  Current topics  Not easy to describe concepts  No vocabulary exists in database Examples  Drug names (Lipitor, Prozac)  Slang  Concepts (Swine flu, oil spill)
  14. 14. Search construction: Vocabulary Keywords Controlled vocabularies What are they?  Set of words or phrases used to describe concepts  Dictionary of accepted terms for a database When to use?  Searching a database that uses one Examples  MeSH (Medical Subject Headings)  EMTREE (Embase)
  15. 15. Search construction: Vocabulary Keywords Controlled vocabularies MeS H
  16. 16. Search construction: Techniques  Truncation  Wild cards  Adjacency  Phrases  Boolean  Parentheses  residen*  an?sthesiology, p?diatrics  screen* adj5 cancer*  “dental education”  “dental implants”[mh] AND “dental restoration failure”[mh]  (“dental implants”[mh] OR implants[title/abstract]) AND (“dental restoration failure”[mh] OR failure[title]) Note: Techniques vary from database to database
  17. 17. Search construction: Techniques  Limits or Filters – use sparingly (language, species, pt)
  18. 18. Search construction: Techniques  Exploding subject headings  Databases handle explosion differently
  19. 19. Search construction: Techniques  Subheadings “dental implants/standards”[mesh]
  20. 20. Search construction: Techniques  Floating subheadings Ovid MEDLINE (extract) 1. exp Arthritis, Rheumatoid/ 2. exp Inflammatory Bowel Diseases/ 3. 4. chronic ulcerative 5. crohn*.tw. 6. 7. rheumatoid 8. or/1-7 9. exp Postoperative Complications/ 10. exp Perioperative Care/ 11. su.fs. 12. or/9-11 13. 8 and 12 PubMed (extract) ("inflammatory bowel diseases"[mh] OR "chronic ulcerative colitis”[tiab] OR cuc[tiab] OR crohn[tiab] OR "crohn's” [tiab] OR crohns[tiab] OR ibd[tiab] OR "rheumatoid arthritis” [tiab]) AND ("postoperative complications"[mh] OR "perioperative care"[mh] OR "surgery”[subheading] OR "post operative"[tiab] OR "postoperative"[tiab])
  21. 21. Search construction: Filters  A predefined search designed to target specific study methodologies (RCTs, Cohort, Systematic Reviews)  Use a validated filter (whenever possible)  Example: PubMed Clinical Queries – Systematic Reviews (systematic review [ti] OR meta-analysis [pt] OR meta-analysis [ti] OR systematic literature review [ti] OR (systematic review [tiab] AND review [pt]) OR consensus development conference [pt] OR practice guideline [pt] OR cochrane database syst rev [ta] OR acp journal club [ta] OR health technol assess [ta] OR evid rep technol assess summ [ta] OR drug class reviews [ti]) OR (clinical guideline [tw] AND management [tw]) OR ((evidence based[ti] OR evidence-based medicine [mh] OR best practice* [ti] OR evidence synthesis [tiab]) AND (review [pt] OR diseases category[mh] OR behavior and behavior mechanisms [mh] OR therapeutics [mh] OR evaluation studies[pt] OR validation studies[pt] OR guideline [pt] OR pmcbook)) OR ((systematic [tw] OR systematically [tw] OR critical [tiab] OR (study selection [tw]) OR (predetermined [tw] OR inclusion [tw] AND criteri* [tw]) OR exclusion criteri* [tw] OR main outcome measures [tw] OR standard of care [tw] OR standards of care [tw]) AND (survey [tiab] OR surveys [tiab] OR overview* [tw] OR review [tiab] OR reviews [tiab] OR search* [tw] OR handsearch [tw] OR analysis [ti] OR critique [tiab] OR appraisal [tw] OR (reduction [tw]AND (risk [mh] OR risk [tw]) AND (death OR recurrence))) AND (literature [tiab] OR articles [tiab] OR publications [tiab] OR publication [tiab] OR bibliography [tiab] OR bibliographies [tiab] OR published [tiab] OR unpublished [tw] OR citation [tw] OR citations [tw] OR database [tiab] OR internet [tiab] OR textbooks [tiab] OR references [tw] OR scales [tw] OR papers [tw] OR datasets [tw] OR trials [tiab] OR meta-analy* [tw] OR (clinical [tiab] AND studies [tiab]) OR treatment outcome [mh] OR treatment outcome [tw] OR pmcbook)) NOT (letter [http://pwt] wORw n.newlmsp.anpiehr. agroticvle/ b[pst]d O/pRu cbommmeednt_ [sptu])bsets/sysreviews_strategy.html
  22. 22. Search construction: Methodologic Filters From PubMed Clinical Queries
  23. 23. Search construction: Methodologic Filters
  24. 24. Sources  PubMed  Ovid MEDLINE  EMBASE  Scopus  Web of Science  PsycINFO  CINAHL  Cochrane Database of Systematic Reviews  Conference Papers Index   ERIC  Proquest Theses & Dissertations  CABI  Google Scholar  Sociological Abstracts  And others…
  25. 25. Sources: PubMed (  Primary biomedical database  22+ million citations  Native interface for MEDLINE dataset  Citations indexed with MeSH
  26. 26. Sources: PubMed
  27. 27. Sources: Ovid MEDLINE  Different interface to search MEDLINE dataset  Heavily used for systematic reviews  Provides additional search functionality (adjacency)  Uses MeSH (like PubMed)
  28. 28. Sources: Ovid MEDLINE
  29. 29. Sources: Ovid MEDLINE
  30. 30. Sources: EMBASE  Similar to PubMed, Ovid  Indexes man more international journals  Drug indexing is a plus  Uses EMTREE  Includes MEDLINE, unless you NOT out
  31. 31. Sources: Web of Science  Citation database  Times cited & conference proceedings  Other ISI databases:  Impact Factors  Biosis Previews
  32. 32. Sources: Other options  Examine the references of articles of relevance  Included studies and relevant reviews  Use cited by features  Set up email alerts  Contact authors, companies, organizations, societies, etc  Search for ongoing studies (prelim data)  Hand search important journals (by Impact Factor, perhaps)  Citation tracking
  33. 33. Reporting
  34. 34. Reporting  See PRISMA statement  “The aim of the PRISMA Statement is to help authors report a wide array of systematic reviews to assess the benefits and harms of a health care intervention. PRISMA focuses on ways in which authors can ensure the transparent and complete reporting of systematic reviews and meta-analyses.”
  35. 35. Reporting  See Cochrane Handbook   Section 6.6  “It should be borne in mind at the outset that the full search strategies for each database will need to be included in an Appendix of the review.”
  36. 36. Reporting  See Cochrane Handbook   Section 6.6  In study flow diagram:  number of unique records identified by the searches;  number of records excluded after preliminary screening (e.g. of titles and abstracts); and  number of records retrieved in full text
  37. 37. Reporting  See Cochrane Handbook   Section 6.6  In abstract:  List all databases searched.  Note the dates of the last search for each database or the period searched.  Note any language or publication status restrictions (but refer to Section 6.4.9).  List individuals or organizations contacted.”
  38. 38. Reporting  See Cochrane Handbook   Section 6.6  In methods:  List all databases searched.  Note the dates of the last search for each database AND the period searched.  Note any language or publication status restrictions  List grey literature sources.  List individuals or organizations contacted.  List any journals and conference proceedings specifically handsearched for the review.  List any other sources searched (e.g. reference lists, the internet).
  39. 39. Reporting  Example
  40. 40. Recap  Spend time developing your search  Search multiple databases  Take notes during process  Give thought to how you want to report on the data collection  Consult an expert searcher
  41. 41. Thanks! Mark MacEachern, MLIS Informationist, Taubman Health Sciences Library