Literature Review Mayyada Wazaify, PhD

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 Review What 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 to Do a Literature Review? It provides a context & legitimacy for your research questions It helps you to think about your topic & gives alternative perspectives at different stages of the research It helps define the methodology It makes the contribution of your research explicit Helps to prevent redundancy

Potential Sources for a Literature Review Books Journals Theses, Conference Papers & Working Papers (Research in Progress) Reference Works Other Information: manufacturers’ leaflets, government information, official statistics Websites Reference works include dictionaries, thesauruses, encyclopedias, almanacs, bibliographies, and catalogs (e.g. catalogs of libraries, museums or the works of individual artists).[

Sources of Drug Information Primary Sources e.g. biomedical journals Secondary Sources e.g. Medline Tertiary Sources e.g. reference books Sources of Drug Information This 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. 7

Web Credibility

Where to go?

What is Pubmed? PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine (NLM) at the National Institutes of Health (NIH) maintains the database

PubMed Overview NLM : 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, the Index 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 PubMed Data base selection menu Search box link to the Advanced search Guided searches and query tools (PubMed Tools)

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

Search 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 the Search button or Enter key to launch the search.

Filters (aspirin resistance) Use filters to narrow your search results. Filter options appear to the left of your results.  Click on a filter to apply it to your search Multiple 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 options To deselect a filter, click the filter name again To clear all of your Filters selections, click Clear 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 Article type: clinical trail and reviews …….1986 Free full text…….477 English language ….. 455 Sex, females ……167 Age , > 65……92

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

Boolean Logic Introduction to Boolean Logic In the context of database searching, Boolean logic 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 operators must be entered in uppercase letters.

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

Boolean Logic NOT: 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 Logic AND: Used to retrieve a set in which each citation contains all search terms. Example : aspirin resistance AND clopidogrel (36)

Boolean Logic Nesting: When using multiple Boolean operators in PubMed, they are processed left to right. Example: aspirin resistance AND clopidogrel OR warfarin……22027 This will retrieve records that include both terms aspirin reisitance AND clopidogrel as well as all records with the term warfarin, whether or not they contain the other two terms.

Boolean Logic To 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)…. 479

Boolean Logic To 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 like and 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.

Truncation Examples: treatment* also finds treatments rehabilitat* finds rehabilitation 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 women organi?ation finds organisation organization finds both English & American spellings think of other English/American spellings healthcare Centre healthcare Center behaviour behavior

Journal search If 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. Click Journals in NCBI Databases from the PubMed home page

Journal search The Summary (default) display in the NLM Catalog includes: the journal title the NLM title abbreviation the print and electronic International Standard Serial Numbers (pISSN and eISSN) the place of publication and name of the publisher the MEDLINE indexing status  the NLM ID (the NLM's unique journal identifier).

Clinical queries There are 3 search filters available from this page Clinical Study Categories Systematic Reviews Medical Genetics Enter your term(s) and click Search  The 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 Review Exercise 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 Review Exercise 1 Select 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 Review Exercise 2 Clinical queries Accidents sleep deprivation…..12 systematic reviews

Key Words Aspirin and heart attack prevention??? “aspirin for heart attack prevention” Aspirin AND Heart AND Attack AND prevention Aspirin heart attack prevention No punctuation, Be specific

Search Authors Yacoub Mohammad Irshaid ??? Irshaid YM OR Advanced Search Builder When stuck: [au]

Examples To search for citations to articles written by Bonnie W. Ramsey about gene therapy for cystic fibrosis ?????? cystic fibrosis gene therapy ramsey bw

Journal To 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 Words Single Citation matcher (HOME PAGE) Scandinavian journal of caring sciences, social investigation, Irshaid

Too many /Too few Pneumonia, Hospital acquired

Publication Date and Number 1980:1981[dp] Advanced, add to history

Mastering Advanced Search Verapamil

Pomelo /Verapamil drug interactions 2- Verapamil metabolism 3- Pomelo/ verapamil metabolism 4- Pomelo/ any other drug interactions

Managing results Display setting : summary format Multiple PubMed citations are displayed by default in the Summary format, which consists of the following: Author name(s): All authors from the MEDLINE record 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: A PubMed Unique Identifier (PMID) is included on each record.

Managing results Display setting : abstract format author 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 from PubMed 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 format The Summary (Text) format is designed for reference lists

Display setting : text format

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Literature review summary Review 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