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Edwin Chan 1 Developing a search strategy 台大新竹分院家醫科 陳宗伯 / 陳孟侃.

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Presentation on theme: "Edwin Chan 1 Developing a search strategy 台大新竹分院家醫科 陳宗伯 / 陳孟侃."— Presentation transcript:

1 Edwin Chan 1 Developing a search strategy 台大新竹分院家醫科 陳宗伯 / 陳孟侃

2 Edwin Chan Evidence-Based Medicine (EBM) Resources 2

3 Edwin Chan Systematic Reviews and Meta- Analyses  The Cochrane Database of Systematic Reviews  The Database of Abstracts of Reviews of Effects (DARE) 3

4 Edwin Chan Critically-Appraised Topics (Evidence Syntheses)  Clinical Evidence  DynaMed  National Guideline Clearinghouse 4

5 Edwin Chan Critically-Appraised Individual Articles (Article Synopses)  The ACP Journal Club  Evidence Updates  Dartmouth EBM Database 5

6 Edwin Chan Unfiltered Resources [Finding an original study]  Pubmed  Medline 6

7 Edwin Chan Background Information/Expert Opinion  UpToDate  eMedicine  National Guideline Clearinghouse 7

8 Edwin Chan 8 Outline  Strategic approach to locating studies  Designing a search strategy  Tips to search PubMed  Documenting a search

9 Edwin Chan 9 Contexts  Clinical care  Clinical education  Clinical research

10 Edwin Chan 10 Finding as much as possible and being strategic Use multiple sources and start with the highest yield Electronic databases -Cochrane Review Group register -Cochrane Central Register of Controlled Trials(CENTRAL) -MEDLINE -EMBASE -Other databases-depending on your topic Reference lists of trials and reviews Handsearching journals and conference proceedings Personal communication

11 Edwin Chan 11 Designing a search strategy  Formulate a focused question(PICO)  Identify search terms from the elements of the focused question  Combine the search terms  Search the database

12 Edwin Chan 12 Focused question  Translate the clinical problem into a focused question Dose preoperative education improve outcomes in patients undergoing lower limb joint replacement?

13 Edwin Chan 13 Extract the PICO terms from the focused question  Does preoperative education improve outcomes in patients undergoing lower limb joint replacement? Patients or problemHip or knee replacement Intervention(s)Preoperative education,information,instruction ControlRoutine or standard care OutcomePain,QOL,mobility,LOS designRCT,systematic reviews

14 Edwin Chan 14 Note  Not all PICOD terms are equally useful for searching Typically start with P & I C is useful if a specific comparator is named e.g. placebo or active treatment D is useful for limiting search to gold-standard designs  Do not have to use all PICOD elements,sometimes just 2 will suffice  Searching is an iterative process (trial and error ) Don ’ t expect to get it right the first time

15 Edwin Chan 15 Searching the database -2methods  Using Free-text terms directly search PubMed bibliographic database using the searchable PICO terms just identified  Using MeSH terms MeSH thesaurus is a standardized dictionary of terms first search the MeSH thesaurus for MeSH terms then search the bibliographic database using the selected MeSH terms

16 Edwin Chan 16

17 Edwin Chan 17 Outline your Strategy Which of the PICOS elements will I initially use? Shall I do both MeSH &/or free-text searches? Shall limit the search

18 Edwin Chan 18 lnitial search strategy  Start with a MeSH search of the P term  Followed by a free – text search of the I term  Combine the 2 searches and check the yield Patients or problemHip or knee replacement[MesH] Intervention(s)Preoperative educationm,information,instruction[Fr ee-text] ControlRoutine or standard care OutcomePain,QOL,mobility,LOS designRCT,systematic reviews

19 Edwin Chan Searching with MeSH terms 19

20 Edwin Chan 20 Search for the MeSH term/s corresponding to the P term/s

21 Edwin Chan 21 Result of MeSH thesaurus search …

22 Edwin Chan 22 Combine MeSH term/s with OR

23 Edwin Chan 23 Search PubMed using combined MeSH terms …

24 Edwin Chan 24 Search PubMed using MeSH terms as Major Topics only …

25 Edwin Chan 25 MeSH Search Results Scroll down to See syntax

26 Edwin Chan 26 Search syntax in Search details box …

27 Edwin Chan Searching with free-text terms 27

28 Edwin Chan 28 Free-text searching for the I term "preoperative education" OR "preoperative instruction" OR "preoperative information"

29 Edwin Chan 29 Free-text Search Results

30 Edwin Chan 30 Check search history by going to Advanced search view …

31 Edwin Chan 31 Combine P and I searches using AND(Advanced search)

32 Edwin Chan 32 Preview of search results (#of hits)

33 Edwin Chan 33 Select additional search limits if necessary

34 Edwin Chan 34 Search with limits

35 Edwin Chan 35 Result of limit search, click on Display Settings arrow

36 Edwin Chan 36 Tips:In order to minimise bias  don ’ t limit search on Language Source(which journal, database etc) Publication status (full article, conference abstract, unpublished etc) Publication date

37 Edwin Chan 37 Searching with Clinical Queries

38 Edwin Chan 38 Search for specific study aims

39 Edwin Chan 39 Select Abstract format from Display Settings … To save references in format exportable to RevMan, choose the MEDLINE display

40 Edwin Chan 40 Save or search results using the Send to menu

41 Edwin Chan 41 Print from the web browser

42 Edwin Chan 42 Documenting your search  important for you, so you coa remember what you ’ ve done  important for users of you review  document What you searched (databases etc) When you search ed (year) How you searched (syntax)

43 Edwin Chan 43 Managing you search history

44 Edwin Chan 44 Saving the search syntax in …

45 Edwin Chan 45 You ’ re My NCBI account

46 Edwin Chan 46 Click on search syntax name to rerun search

47 Edwin Chan 47 Saving the search syntax in you ’ re my NCBI account(alt)

48 Edwin Chan 48 Name the search syntax & save

49 Edwin Chan 49 Specify any update options in the Settings dialog box

50 Edwin Chan 50 Return to the list of your Saved Searches

51 Edwin Chan 51 Manage searches from Saved Search list-search, delete,edit

52 Edwin Chan 52 Search strategy summary 3.Publication types e.g.RCTs 1.Patient/Problem (MeSH headings OR text words) 2.Intervention (MeSH headings OR text words) AND

53 Edwin Chan 53 What if …  Too many references is your topic too broad? is your question focused enough ? have you used enough PICO elements? have you mistakenly used OR instead of AND to combine across PICO elements try using limits try using NOT to exclude specific articles

54 Edwin Chan 54 What if …  Too few references is your topic too focused? try using MeSH searches too capture all synonyms have you used too many PICO elements? have you mistakenly used AND instead of OR to combine within PICO elements don ’ t use NOT have you left the limits function on by mistake? try checking known references for relevant key words are you searching the right database? is the terminology just too unstandardized & inconsistently used in this field?

55 Edwin Chan 55 Additional points  No right time to stop searching;be guided by returns and resources  Ideas for search terms from citatins you know of;try them and check returns  Use a referencing database to manage citations  Can import references into RevMan 5- display searches in MEDLINE format & save


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