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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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Edwin Chan Evidence-Based Medicine (EBM) Resources 2
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Edwin Chan Systematic Reviews and Meta- Analyses The Cochrane Database of Systematic Reviews The Database of Abstracts of Reviews of Effects (DARE) 3
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Edwin Chan Critically-Appraised Topics (Evidence Syntheses) Clinical Evidence DynaMed National Guideline Clearinghouse 4
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Edwin Chan Critically-Appraised Individual Articles (Article Synopses) The ACP Journal Club Evidence Updates Dartmouth EBM Database 5
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Edwin Chan Unfiltered Resources [Finding an original study] Pubmed Medline 6
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Edwin Chan Background Information/Expert Opinion UpToDate eMedicine National Guideline Clearinghouse 7
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Edwin Chan 8 Outline Strategic approach to locating studies Designing a search strategy Tips to search PubMed Documenting a search
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Edwin Chan 9 Contexts Clinical care Clinical education Clinical research
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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
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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
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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?
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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
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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
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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
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Edwin Chan 16 http://www.ncbi.nlm.nih.gov/pubmed
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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
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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
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Edwin Chan Searching with MeSH terms 19
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Edwin Chan 20 Search for the MeSH term/s corresponding to the P term/s
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Edwin Chan 21 Result of MeSH thesaurus search …
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Edwin Chan 22 Combine MeSH term/s with OR
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Edwin Chan 23 Search PubMed using combined MeSH terms …
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Edwin Chan 24 Search PubMed using MeSH terms as Major Topics only …
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Edwin Chan 25 MeSH Search Results Scroll down to See syntax
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Edwin Chan 26 Search syntax in Search details box …
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Edwin Chan Searching with free-text terms 27
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Edwin Chan 28 Free-text searching for the I term "preoperative education" OR "preoperative instruction" OR "preoperative information"
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Edwin Chan 29 Free-text Search Results
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Edwin Chan 30 Check search history by going to Advanced search view …
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Edwin Chan 31 Combine P and I searches using AND(Advanced search)
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Edwin Chan 32 Preview of search results (#of hits)
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Edwin Chan 33 Select additional search limits if necessary
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Edwin Chan 34 Search with limits
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Edwin Chan 35 Result of limit search, click on Display Settings arrow
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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
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Edwin Chan 37 Searching with Clinical Queries
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Edwin Chan 38 Search for specific study aims
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Edwin Chan 39 Select Abstract format from Display Settings … To save references in format exportable to RevMan, choose the MEDLINE display
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Edwin Chan 40 Save or e-mail search results using the Send to menu
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Edwin Chan 41 Print from the web browser
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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)
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Edwin Chan 43 Managing you search history
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Edwin Chan 44 Saving the search syntax in …
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Edwin Chan 45 You ’ re My NCBI account
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Edwin Chan 46 Click on search syntax name to rerun search
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Edwin Chan 47 Saving the search syntax in you ’ re my NCBI account(alt)
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Edwin Chan 48 Name the search syntax & save
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Edwin Chan 49 Specify any e-mail update options in the Settings dialog box
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Edwin Chan 50 Return to the list of your Saved Searches
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Edwin Chan 51 Manage searches from Saved Search list-search, delete,edit
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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
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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
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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?
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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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