Literature Review

Mayyada Wazaify, PhD

Literature Review

What is Literature Review?A literature review is an account of what has been published on a topic by accredited scholars and researchers

A good literature review shows knowledge and is a critical examination of existing literature of a certain field.

A good literature review is not a description of previous work, but provides a novel and original synthesis.

A good literature review leads to new ways of looking at a topic and identifies gaps in the literature.

Skills You need:information seeking: the ability to scan the literature efficiently, using manual or computerized methods, to identify a set of useful articles and books

critical appraisal: the ability to apply principles of analysis to identify unbiased and valid studies.

The Contents of a Literature ReviewWhat is already known about the topic?What needs to be said critically about what is already known?Has anyone else ever done anything similar to what is proposed?Has anyone else done anything that is related?Where does your work fit with what has gone before?Why is your research worth doing in the light of what has already been done?

(Source: Silverman 2000:227)Why is it Important toDo a Literature Review?It provides a context & legitimacy for your research questionsIt helps you to think about your topic & gives alternative perspectives at different stages of the researchIt helps define the methodologyIt makes the contribution of your research explicitHelps to prevent redundancyPotential Sources for a Literature ReviewBooksJournalsTheses, Conference Papers & Working Papers (Research in Progress)Reference WorksOther Information: manufacturers leaflets, government information, official statisticsWebsites

Reference works includedictionaries, thesauruses,encyclopedias, almanacs, bibliographies, and catalogs (e.g. catalogs of libraries, museums or the works of individual artists).[6

Primary Sources e.g. biomedical journals

Secondary Sources e.g. Medline

Tertiary Sources e.g. reference books

Sources of Drug Information7This categorization used to be straightforward. However, the technological improvements have blurred the situation. Some tertiary, secondary and primary sources do exist in different format (e.g. hard copy, CD-ROM or web-based or microforms

Microforms are any form, either films or paper, containing microreproductions[1] of documents for transmission, storage, reading, and printing. Microform images are commonly reduced about 25 times from the original document size. For special purposes, greater optical reductions may be used.All microform images may be provided as positives or negatives, more often the latter.Three formats are common: microfilm (reels), aperture cards and microfiche (flat sheets). Microcards, a format no longer produced, were similar to microfiche, but printed on cardboard rather than photographic film.7Web Credibility

Where to go?

What is Pubmed?PubMedis a free search engine accessing primarily theMEDLINEdatabaseof references and abstracts on life sciences and biomedical topics.

TheUnited States National Library of Medicine(NLM) at theNational Institutes of Health (NIH) maintains the database

PubMed OverviewNLM : indexing the biomedical literature since 1879, to help provide health professionals access to information necessary for research, health care, and education

What was once a printed index to articles, theIndex Medicus, became a database now known as MEDLINE. MEDLINE contains journal citations and abstracts for biomedical literature from around the world.

Since 1996, free access to MEDLINE has been available to the public online via PubMed.

Navigating PubMedData base selection menuSearch boxlink to the Advanced searchGuided searches and query tools (PubMed Tools)database selection menu

database selection menu, where you can choose between PubMed and other NCBI databasesthe last four databases you searched will appear at the top

14Search box

link to the Advanced search

Guided searches and query tools (PubMed Tools)

Help, Pubmed tutorial, FAQs

Building the search To search PubMed, you can simply enter search terms in the search box. Automatic suggestions will display as you type your search terms. Click Turn off to temporarily disable the auto suggest feature.PubMed contains many records, so be as specific as possible.The search box will always be available to you on any page in PubMed: the Home page, a results screen, the Clipboard, or any other.Any combination of search terms can be typed in the search box. Click theSearchbutton or Enter key to launch the search.

Filters (aspirin resistance) FiltersUse filters to narrow your search results.Filter options appear to the left of your results.

Click on a filter to apply it to your searchMultiple selections are allowed.

Active Filters appear above your search results.Only the most popular filters display by default. Click Show additional filters to view more optionsTo deselect a filter, click the filter name againTo clear all of your Filters selections, clickClear all.Note: Only filters which are valid for your search results will appear. For example, if no Clinical Trials are in your results, the filter for Clinical Trials will not appear.

Aspirin resistance example Aspirin resistance Article type: clinical trail and reviews .1986Free full text.477English language .. 455Sex, females 167 Age , > 6592

Filters Myocardial infarction filters Text availability (guideline)Publication dates (2 years old)Language (English)End up with 19 texts from 198707

Boolean LogicIntroduction to Boolean LogicIn the context of database searching,Booleanlogic refers to the logical relationships among search terms.The Boolean operators AND, OR, NOT can be used to combine search terms in PubMed.In PubMed, Boolean operatorsmust be entered in uppercase letters.

Boolean LogicOR:Used to retrieve a set in which each citation containsat least oneof the search terms.Use OR when you want to pull together articles on similar topics.Example : aspirin resistance OR clopidogrel (908)

Boolean LogicNOT:Retrieves a set from which citations to articles containing specified search terms following the NOT operator are eliminated.Example: aspirin resistance NOT clopidogrel (56)

Boolean LogicAND:Used to retrieve a set in which each citation containsallsearch terms.Example : aspirin resistance AND clopidogrel (36)

Boolean LogicNesting:When using multiple Boolean operators in PubMed, they are processed left to right.Example:aspirin resistance AND clopidogrel OR warfarin22027This will retrieve records that include both termsaspirin reisitanceANDclopidogrel as well as all records with the termwarfarin, whether or not they contain the other two terms.

Boolean LogicTo change the order in which terms are processed, enclose the terms(s) in parentheses. The terms inside the set of parentheses will be processed as a unit and then incorporated into the overall strategy.This is called nesting.Example: Aspirin resistance AND (clopidogrel OR warfarin). 479Boolean LogicTo review:Boolean operators AND, OR and NOT must be entered in UPPERCASE.AND is the default operator used in PubMed. If you do not include Boolean operators in your search, PubMed will automatically use AND between terms.PubMed processes Boolean connectors left-to-right.You can change the order of processing by nesting an individual concept in parentheses. The terms inside the parentheses will be processed as a unit and then incorporated into the overall strategy.

Quiz Which of the following PubMed search strategies will retrieve citations on the topic of allergies to eggs or peanuts?allergies NOT peanuts AND eggs allergies and (peanuts or eggs) allergies AND peanuts OR eggs allergies AND (peanuts OR eggs)Phrase searching Do NOT use quotes until you first try your search without them.If you determine that PubMed processed your search differently than you would likeand you want to force a phrase search, you can do so by:Enclosing the phrase in double quotes:example; aspirin resistance vs. aspirin resistance 1986 vs. 572

Truncation *Truncation can be used when you want PubMed to find all terms that begin with a given text string. Truncation is represented by the asterisk (*), sometimes referred to as a "wildcard."For example, let's say you are trying to search all terms that have the root, mimic.

PubMed restricts retrieval to the first 600 variations of the truncated term. When this occurs, PubMed will display a warning message.

Many truncations within one search strategy may overwhelm system resources and cause the search to "time out" or fail.32Truncation Examples:

rehabilitat* findsrehabilitation rehabilitate rehabilitates rehabilitated Useful for plurals: treatment* also finds treatments

Entering keywords using wildcards

Find variations within the same keyword using ?

? can represent any letter

wom?n finds woman womenorgani?ationfinds organisation organization

finds both English & American spellings

think of other English/American spellings

healthcare Centre healthcare Centerbehaviour behavior

34Journal searchIf you want to get information about a specific journal, how could you know these details?Frequency of publication? Since when? Where is it published? Journal search The NLM Catalog has a special tool that allows you to look up information about a PubMed journal. ClickJournals in NCBI Databasesfrom the PubMed home pageJournal search The Summary (default) display in the NLM Catalog includes: the journal titlethe NLM title abbreviationthe print and electronic International Standard Serial Numbers (pISSN and eISSN)the place of publication and name of the publisherthe MEDLINE indexing statusthe NLM ID (the NLM's unique journal identifier).

Clinical queries There are 3 search filters available from this pageClinical Study CategoriesSystematic ReviewsMedical GeneticsEnter your term(s) and click SearchThe first 5 retrieved citations are displayed. Choose your Category, Scope or Topic (if appropriate).

Clinical queries: systematic reviews This feature is provided to help clinicians locate systematic reviews and similar articles.It retrieves systematic reviews, meta-analyses, reviews of clinical trials, evidence-based medicine, consensus development conferences, and guidelines. Example: Aspirin resistance: 61 systematic reviews Search Tools ReviewExercise 1:Use the NLM Catalog Journal search page to see if PubMed includes the journal,International Journal of Clinical Pharmacy. If so, retrieve all PubMed citations from this journal. Exercise 2:Use the Clinical Queries to find systematic reviews for accidents caused by sleep deprivation.

Search Tools ReviewExercise 1Select Journals in NCBI Databases from PubMed's home page.

Type a few characters from the journal title in the search box, select the correct title and click Search

Click the PubMed link in the right column to retrieve all the citations to this journal in PubMed

Search Tools ReviewExercise 2Clinical queries Accidents sleep deprivation..12 systematic reviews Key WordsAspirin and heart attack prevention???

aspirin for heart attack preventionAspirin AND Heart AND Attack AND preventionAspirin heart attack prevention

No punctuation, Be specific

Search AuthorsYacoub Mohammad Irshaid???

Irshaid YM

OR Advanced Search Builder

When stuck: [au]

ExamplesTo search for citations to articles written by Bonnie W. Ramsey about gene therapy for cystic fibrosis ??????cystic fibrosis gene therapy ramsey bwJournalTo search for articles about drosophila in the journal Molecular Biology of the Cell enter the following in the search box:

molecular biology of the cell drosophila

Salad WordsSingle Citation matcher (HOME PAGE)

Scandinavian journal of caring sciences, social investigation, Irshaid

Too many /Too fewPneumonia,Hospital acquired Publication Date and Number 1980:1981[dp]

Advanced, add to history

Mastering Advanced SearchVerapamil

Pomelo /Verapamildrug interactions1- Pomelo/Verapamil2- Verapamil metabolism3- Pomelo/ verapamil metabolism 4- Pomelo/ any other drug interactions

Managing results Display setting : summary formatMultiple PubMed citations are displayed by default in the Summary format, which consists of the following:Author name(s):All authors from the MEDLINErecord are displayed.[Show Me]

Corporate Author:Identifies the corporate authorship of an article. Corporate names display exactly as they appear in the journal.Note:Citations indexed pre-2000 and some citations indexed in 2000-2001 retain corporate authors at the end of the title field.

Source:Provides the journal title abbreviations, date of publication, volume, issue, and page numbers of the article. A mouseover of the journal title abbreviation displays the full journal title.Additional notations:Original language (if other than English); Publication Type (if the article is a review or retracted publication); and the notation "No abstract available" (if PubMed does not carry an abstract for the item). Included as appropriate.

Tags:[PubMed - as supplied by publisher],[PubMed - in process],[PubMed - indexed for MEDLINE], or[PubMed]tags.

Identification number:APubMed Unique Identifier (PMID)is included on each record.

Managing results Display setting : abstract formatauthor names as search links to author searches.The affiliation (address) of the authors at the time of publication. NOTE: Only the first author's affiliation is included for records added prior to 2014.

Abstract, if one is present, from the published article.

Annotations to associated citations (e.g., errata), if present.

A preview of images from the article fromPubMed Central, if available.

Links to full-text of the article at provider's Web site or PubMed Central, if available.

Links to Related Citations.

Links to related resources in external sources (LinkOut).

Managing results Display setting : text formatThe Summary (Text) format is designed for reference lists

Display setting : text format

Send to

Tips onGoogle Scholar

H-Index

i-10 index

Impact FactorLiterature review summaryReview the literature for articles talking about aspirin resistance in male patients older than 65 years with a history of stroke or diabetes. Find full texts

Decide whether to submit your article to Saudi medical journal keeping in mind that you wish your article to appear in Pubmed

Find the latest full guideline for treatment of unstable angina

Export citations related to articles in the first question to EndNote program to use in writing your proposal