Searching the Medical Literature
Robin Featherstone
Clinical Medicine Librarian
UWO
rfeathe@uwo.ca
http://www.slideshare.n...
Objectives
• List four categories of information resources
• Apply selection criteria to identify appropriate
information ...
Level of Evidence Pyramid
Qualitative Studies
Systems, Synopses & Summaries
Systems Synopses Summaries
Few exist Number in the thousands Fewer than 50,000
Textbook-like...
Criteria for Selecting a Resource
1. Soundness of evidence-based approach
2. Comprehensiveness and specificity
3. Ease of ...
Questions to Ask
• Bias? Conflict of interest?
• Evidence grading or ranking applied?
• Links?
• Discipline coverage?
• Co...
Studies
• Number in the millions
• No processing of evidence – must individually
assess
• Require searching large databases
Available from Western Libraries (or for free)
Systems Synopses Syntheses Studies
• ACP PIER
• DynaMed
• Clinical Evidence...
HOW TO SEARCH STUDIES
A Comprehensive Search is...
• Systematic
• Explicit
• Reproducible
7 tasks in a comprehensive search
1. Develop a search statement or question
2. Select a source
3. Choose search terms
4. R...
How questions influence search
results
Relevancy
Retrieval
(# of search
results)
Broad
Questions
Narrow
Questions
High =
l...
Sample Search Statements
• I am looking for articles about osteoarthritis of the
knee.
– 13,886 articles in PubMed
• I am ...
Turn your statement into a
strategy
1. Break you question into concepts
2. Identify subject headings for each concept
3. I...
Does hand washing prevent MRSA?
in the ICU?Hand washing MRSA ICU Prevention
Handwashing
[MeSH]
Methicillin-
Resistant
Stap...
Different databases have different
subject headings
• Tips:
– Complete a concept map for each database that you search
– S...
Some key operators in Ovid
Operator Command
$ Truncation (finds alternate endings)
? Wildcard (finds alternate spellings)
...
How does patient adherence to medication
regimens influence outcomes following surgery
for myocardial infarction?
Source:
...
Running your search
Running your search(es)
• Start with your first concept
– Search for the subject headings first
– Then search keywords
– C...
Running your search(es)
Search #2 =
Search #3 =
Search #4 =
Search #5 = #1 OR #2 OR #3 OR #4
Search #1 =
Concept 1
Search ...
Applying practical & methodological
screening criteria
Screening
• Two kinds: practical and methodological
• Why?
– Use practical screening to identify a broad range
of potentia...
Practical Screening Criteria – some
examples
1. Date of publication
– only studies conducted between 2005 and 2010
1. Part...
Methodological Screening Criteria -
some questions to ask
• Is the study’s research design internally &
externally valid?
...
Applying Screens (or limits)
• Apply practical screens by using “limits” (may
also be called “search options”)
• Apply met...
Next steps
Moving to another source
• Retain as much of your original strategy as
possible
• Recognize that subject headings will be
...
Working with your results
• Export search results from each database or
website into a citation manager (i.e.,
RefWorks)
•...
Synthesizing the results
Look for Patterns
• What conclusions did these studies reach?
• Which studies agreed/disagreed with the
consensus?
• Consi...
Use your results to...
1. Describe current knowledge about your
research topic
2. Support the need for and significance of...
Recap
1. What is a quality search?
2. Develop a research question that’s ________
3. Which boolean operator do you use to
...
Questions
Robin Featherstone
Clinical Medicine Librarian
UWO
rfeathe@uwo.ca
Selinda Berg
Clinical Medicine Librarian
Winds...
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Searching the medical literature aug 2010

  1. 1. Searching the Medical Literature Robin Featherstone Clinical Medicine Librarian UWO rfeathe@uwo.ca http://www.slideshare.net/featherr Selinda Berg Clinical Medicine Librarian Windsor sberg@uwindsor.ca
  2. 2. Objectives • List four categories of information resources • Apply selection criteria to identify appropriate information resource • List five databases to find primary studies • Strategize and execute a systematic, explicit and reproducible search of the biomedical literature
  3. 3. Level of Evidence Pyramid Qualitative Studies
  4. 4. Systems, Synopses & Summaries Systems Synopses Summaries Few exist Number in the thousands Fewer than 50,000 Textbook-like; integrate clinical evidence with other types of info; directed at clinical practice decisions Summaries of studies and systematic reviews; includes guides or advice from expert clinicians Systematic reviews of articles and guidelines; you assess and make decisions Very easy to use Easy to use May require searching
  5. 5. Criteria for Selecting a Resource 1. Soundness of evidence-based approach 2. Comprehensiveness and specificity 3. Ease of use 4. Availability
  6. 6. Questions to Ask • Bias? Conflict of interest? • Evidence grading or ranking applied? • Links? • Discipline coverage? • Consistent and quick to search? • Cost? • Available in my location?
  7. 7. Studies • Number in the millions • No processing of evidence – must individually assess • Require searching large databases
  8. 8. Available from Western Libraries (or for free) Systems Synopses Syntheses Studies • ACP PIER • DynaMed • Clinical Evidence • UpToDate • Micromedex • ACP Journal Club • InfoPOEMS (Essential Evidence Plus) • DARE (Database of Reviews of Effects) Centre for Reviews and Dissemination • Cochrane Database of Systematic Reviews  Cochrane Library • US National Guidelines Clearinghouse • MEDLINE  PubMed  Ovid  Pubget • EMBASE • SCOPUS • Cochrane Controlled Trials Registry (CCTR)  Cochrane Library • CINAHL • PsycINFO • Web of Science •TRIP Database Find at: www.lib.uwo.ca/programs/undergraduatemedicaleducation/
  9. 9. HOW TO SEARCH STUDIES
  10. 10. A Comprehensive Search is... • Systematic • Explicit • Reproducible
  11. 11. 7 tasks in a comprehensive search 1. Develop a search statement or question 2. Select a source 3. Choose search terms 4. Run the search 5. Apply practical screens (limits) 6. Apply methodological screens 7. Synthesize the results
  12. 12. How questions influence search results Relevancy Retrieval (# of search results) Broad Questions Narrow Questions High = lots of articles Low = very few articles High = directly relevant articles Low = mostly irrelevant articles
  13. 13. Sample Search Statements • I am looking for articles about osteoarthritis of the knee. – 13,886 articles in PubMed • I am looking for RCTs on arthroscopic surgery for osteoarthritis of the knee that include placebo surgery as a control. – 9 articles in PubMed • I am looking for RCTs on arthroscopic surgery conducted in latino females with type 1 diabetes mellitus. – 0 articles in PubMed
  14. 14. Turn your statement into a strategy 1. Break you question into concepts 2. Identify subject headings for each concept 3. Identify keywords for each concept • Tips: – Use a “target article” to help identify search terms – Use a strategy worksheet to keep track of your terms: http://www.lib.uwo.ca/files/taylor/grad/Search_Strategy_Worksheet.pd f
  15. 15. Does hand washing prevent MRSA? in the ICU?Hand washing MRSA ICU Prevention Handwashing [MeSH] Methicillin- Resistant Staphylococcus aureus [MeSH] Intensive care units [MeSH] + Handwash$.mp. Methicillin resistant staphylococcus aureus.mp. Intensive care unit$.mp. Prevent$.mp. Hand wash$.mp. MRSA.mp. ICU.mp. Hand disinfect$.mp. Critical care unit$.mp. Surgical scrub$.mp. Hand clean$.mp.
  16. 16. Different databases have different subject headings • Tips: – Complete a concept map for each database that you search – Select subject headings that are the closest match for your concept (remember: systematic, explicit and reproducible) – Pay attention to “explode” commands – some databases will search related headings by default, others will not Database Subject Headings Medline MeSH EMBASE EMTREE CINAHL CINAHL Headings Cochrane Library MeSH Web of Science N/A Scopus N/A
  17. 17. Some key operators in Ovid Operator Command $ Truncation (finds alternate endings) ? Wildcard (finds alternate spellings) .mp. Mapping Alias (tells Ovid to search for your term in the Title, Abstract, Subject Headings, Table of Contents and Key Phrase Identifier fields) – useful for lit. reviews because it is broad () Parentheses control the order of search operations Adj Adjacency operator (can be followed by a number) tells Ovid terms must appear adjacent to one another AND all terms must appear in results OR any terms will appear in results Note: These are recommended operators for research lit reviews. There are many, many more operators... Use Ovid‘s Help menu to locate them. Or see: http://content.library.utoronto.ca/gerstein/subjectguides/ovidmedline_shortcuts.pdf
  18. 18. How does patient adherence to medication regimens influence outcomes following surgery for myocardial infarction? Source: Practical Screens:
  19. 19. Running your search
  20. 20. Running your search(es) • Start with your first concept – Search for the subject headings first – Then search keywords – Combine these synonymous searches with OR using your search history • Repeat for your second, third, and subsequent concepts • Finally, combine large search results set with AND
  21. 21. Running your search(es) Search #2 = Search #3 = Search #4 = Search #5 = #1 OR #2 OR #3 OR #4 Search #1 = Concept 1 Search #6 = Search #7 = Search #8 = Search #9 = Concept 2 Search #10 = #6 OR #7 OR #8 OR #9 Search #11 = #5 AND #10 Results
  22. 22. Applying practical & methodological screening criteria
  23. 23. Screening • Two kinds: practical and methodological • Why? – Use practical screening to identify a broad range of potentially useful studies – Use methodological screening to identify the best available studies
  24. 24. Practical Screening Criteria – some examples 1. Date of publication – only studies conducted between 2005 and 2010 1. Participants of subjects – only children 6 to 12 years of age 1. Publication language – only materials written in English 1. Research design – only clinical trials
  25. 25. Methodological Screening Criteria - some questions to ask • Is the study’s research design internally & externally valid? • Are the data sources used in the study reliable & valid? • Are the analytic methods appropriate? • Are the results meaningful in practical & statistical terms?* *Fink, A. (2005). Conducting Research Literature Reviews. London: Sage.
  26. 26. Applying Screens (or limits) • Apply practical screens by using “limits” (may also be called “search options”) • Apply methodological screens by reading through the articles
  27. 27. Next steps
  28. 28. Moving to another source • Retain as much of your original strategy as possible • Recognize that subject headings will be different (or non-existent) • Keep track of your search terms using a new concept map
  29. 29. Working with your results • Export search results from each database or website into a citation manager (i.e., RefWorks) • Remove duplicates • Remove inappropriate studies by applying methodological screens
  30. 30. Synthesizing the results
  31. 31. Look for Patterns • What conclusions did these studies reach? • Which studies agreed/disagreed with the consensus? • Consider using a synthesis matrix: www.ncsu.edu/tutorial_center/writespeak/download/Synthesis.pdf
  32. 32. Use your results to... 1. Describe current knowledge about your research topic 2. Support the need for and significance of new research 3. Explain research findings 4. Describe the quality of a body of research* *Fink, A. (2005). Conducting Research Literature Reviews. London: Sage.
  33. 33. Recap 1. What is a quality search? 2. Develop a research question that’s ________ 3. Which boolean operator do you use to combine synonymous search terms? 4. What screens should you apply to your results?
  34. 34. Questions Robin Featherstone Clinical Medicine Librarian UWO rfeathe@uwo.ca Selinda Berg Clinical Medicine Librarian Windsor sberg@uwindsor.ca

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