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 Evaluating your literature searching

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

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.

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. The role of the literature review

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 How to do a literature search

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)

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 How to do a literature search

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

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

Problem : Would aspirin reduces CVD events in diabetics? Final question : For patients with diabetes mellitus, will aspirin prophylaxis produces fewer cardiovascular overall complications? ItemDescription PopulationPatients with diabetes InterventionCVD events with aspirin ComparisonCompared to method of ‘no aspirin’ OutcomeFewer for all morbities and mortalities PICO

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?

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 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 How to do a literature search

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

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

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

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

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

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

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)

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 How to do a literature search

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”

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 How to do a literature search

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

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

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 Google Scholar

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

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

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

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

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 How to do a literature search

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

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.

Managing data NoFirst author YearPrevalence ObjectiveRemarks 12 1Awang201160%Significant hypothesis Not sig reason Important points Suggestions etc 2

HOW TO USE OVID PRACTICAL SESSION

1. Log in 2. Klik

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Klik Ovid

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1. Keywords/Boolean 2. Limit

Task To perform literature search on.....

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HOW TO USE PUBMED Practical session

Let’s use this search: What’s the evidence for the use of montelukast in the management of childhood asthma

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HOW TO USE PUBMED Practical session

1. Create new folder 2. Create ‘asthma’ file

1. Search topic

1. Click,drag and drop at the ‘asthma’ file 2. Drop here

1. Click,drag and drop at the ‘asthma’ file

1. Locate PDF :Wizfolio will locate the article

End of the beginning….