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How to do a literature search

How to do a literature search. Saharuddin Ahmad Aida Jaffar Department of Family Medicine. Outline. The role of the literature review Types of evidence Formulating answerable questions Sources of evidence Search techniques Optimal search strategies Online tools

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How to do a literature search

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  1. How to do a literature search Saharuddin Ahmad Aida Jaffar Department of Family Medicine

  2. Outline • The role of the literature review • Types of evidence • Formulating answerable questions • Sources of evidence • Search techniques • Optimal search strategies • Online tools • Evaluating your literature searching

  3. How to do a literature search • The role of the literature review • Types of evidence • Formulating answerable questions • Sources of evidence • Search techniques • Optimal search strategies • Online tools • Evaluating your literature search

  4. The role of the literature review • Exposes main gaps in knowledge and identifies principal areas of dispute and uncertainty (Mays et al, 2001). • Identify findings from multiple examples of research in the same area. • Explore explanations for discrepancies.

  5. The role of the literature review The role of the literature review • Define terminology or identify variations in definitions used by researchers. • Identify appropriate research methodologies. • Identify validated scales and instruments.

  6. How to do a literature search How to do a literature search • The role of the literature review • Types of evidence • Formulating answerable questions • Sources of evidence • Search techniques • Optimal search strategies • Online tools • Evaluating your literature search

  7. Types of evidence • Prediction – Models, case studies ,documentary analysis • Historical – documentary analysis, case studies, narratives • Intervention – experimental studies • Exploration – literature review, theory building, consensus processes • Attitudes – psychological research • Qualitative - using specific qualitative techniques • Causation – observational studies (e.g. case control)

  8. How to do a literature search How to do a literature search • The role of the literature review • Types of evidence • Formulating answerable questions • Sources of evidence • Search techniques • Optimal search strategies • Online tools • Evaluating your literature searching

  9. Formulating answerable questions • Translates “Aims” into achievable and focused tasks • Helps to identify the likely research designs to answer the research question • Helps in constructing the literature search

  10. PICO A method to formulate a precise question : • Population • Intervention • Comparison • Outcome

  11. PICO Problem : Would aspirin reduces CVD events in diabetics? Final question : For patients with diabetes mellitus, will aspirin prophylaxis produces fewer cardiovascular overall complications?

  12. Some types of question • Prediction – What is the likely result of X? • Historical – How have we got from A to B? • Intervention – Is doing Y better than doing Z? • Exploration – What are the possible explanations for A? • Attitudes – How do people feel about B? • Causation – What are the likely causes of C? • Measurement – What is the size of X, how often does it occur etc? • Characterisation – How can we understand and specify W?

  13. How to do a literature search How to do a literature search • The role of the literature review • Types of evidence • Formulating answerable questions • Sources of evidence • Search techniques • Optimal search strategies • Online tools • Evaluating your literature searching

  14. How to do a literature search How to do a literature search • The role of the literature review • Types of evidence • Formulating answerable questions • Sources of evidence • Search techniques • Optimal search strategies • Online tools • Evaluating your literature searching

  15. http://www.nlm.nih.gov/nichsr/ehta/chapter4.html

  16. Search term / Key words • Uses your own words and searches words & phrases to retrieve records ie diabetes, aspirin, ischaemic heart disease • Some problems: • Plurals: e.g. child or children • Different spellings: e.g. esthetic or aesthetic • Different terminology: e.g. pavement or sidewalk • Prefixes: prenatal, pre natal, pre-natal • Different names : Type II diabetes, diabetes mellitus, diabetes

  17. Database features to support natural language • Truncation (e.g. *, $) used to search for different word stems and word endings • e.g. use comput* to find computer, computers, computed, computing, etc. • Wild cards (e.g. *, ?) used to search for spelling variants • e.g. use leuk*mia to find leukaemia or leukemia • Proximity and adjacency operators (e.g. adj or near) • e.g. motor near2 accidents

  18. Database features to support controlled vocabulary • A Thesaurus e.g. MeSH – medical subject heading terms) • Mapping • Explode functions • “See Under”, “Used For” and “See Also” references

  19. Boolean - OR Use to combine like terms or terms within the same concept DM ED DM OR ED

  20. Boolean - AND Use to combine together different concepts DM ED DM AND ED

  21. Boolean - NOT Use to exclude terms from your search DM ED DM NOT ED

  22. Other search techniques • Reference chaining: Follow up references from reference lists of relevant articles • Hand searching: Identify key journals in your field and browse them cover to cover • Relevance feedback: Look at subject indexing for a key reference and use to modify your search terms (Also “See Related Records” features)

  23. How to do a literature search How to do a literature search • The role of the literature review • Types of evidence • Formulating answerable questions • Sources of evidence • Search techniques • Optimal search strategies • Online tools • Evaluating your literature searching

  24. What is an optimal search strategy? “optimal permutations of search terms found in the titles, abstracts or the subject indexing of relevant articles that have been demonstrated to have a high correlation with study quality” “pre-prepared search strategies, previously referred to as ‘search filters’, ‘quality filters’, ‘hedges’ or ‘optimal search strategies’ developed for use with particular databases to retrieve specific types of evidence more effectively”

  25. How to do a literature search How to do a literature search • The role of the literature review • Types of evidence • Formulating answerable questions • Sources of evidence • Search techniques • Optimal search strategies • Online Tools • Evaluating your literature searching

  26. Online Tools • Google Scholar • Portal Perpustakaan PPUKM • Pubmed • Ovid • Science direct • Scopus • Springer links

  27. Google Scholar • Using Boolean Expressions NOT (minus sign) • ED –DM • Search for ED while excluding DM from results • Exact strings “Diabetes mellitus”, “erectile dysfunction” If results is too large, use the “Search within results” option

  28. Google Scholar Google • Wildcards ‘*’/’?’ - Replace wildcard with any combination of characters DM* or T2DM* - DM? or T2DM? • Site search – Restrict your search to a particular site • site:domain.com • Example: cluster computing site:*.edu

  29. Wildcards library.oakland.edu/coursePages/handouts/wildcards.pdf‎

  30. The National Library of Medicine • Part of the National Institutes of Health (NIH) • The world’s largest biomedical library; it produces: • PubMed = Index to world’s biomedical literature • MedlinePlus = Patient education & consumer health information • ClinicalTrials.gov = Database of clinical trials

  31. MEDLINE • The world’s largest biomedical database • Over 5,000 journals indexed, with worldwide coverage • Covers all aspects of biosciences and healthcare • Database of 16+ million journal citations, 1950 to the present • 90% are in English ; 79% have abstracts • The primary component of PubMed

  32. PubMed • PubMed is a tool to search: • MEDLINE (1950 to present) • In-process & publisher-supplied citations (some before they are published in hard copy) • Citations from some older materials not yet upgraded with MEDLINE indexing, some out-of-scope articles from MEDLINE journals, and some life sciences journals that submit full text to PubMedCentral • Produced by NCBI • National Center for Biotechnology Information, part of NLM • Accessible worldwide on the Web at no charge

  33. How to do a literature search How to do a literature search • The role of the literature review • Types of evidence • Formulating answerable questions • Sources of evidence • Search techniques • Optimal search strategies • Online tools • Evaluating your literature searching

  34. Relevant Not Relevant Retrieved Use to generate additional search terms Eliminate terms with poor yield Not Retrieved Use reference lists from key articles to identify these No further action required Evaluating your search strategy

  35. And finally … • Documenting a search • Helps to avoid duplication, allows replication in future • e.g. date of search, sources searched, no. of hits, details of strategy, etc. • Reference management • Reference Manager, EndNote, wizfolio etc.

  36. Managing data

  37. PRACTICAL SESSION How to use Ovid

  38. 2. Klik 1. Log in

  39. Scroll down

  40. Klik Ovid

  41. 1 2 3

  42. 1. Keywords/Boolean 2. Limit

  43. Task • To perform literature search on.....

  44. 2 3 1

  45. 2 4 3 1

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