This was given as a part of the course of Research & Evidence-Based Medicine given to fourth-year medical students (2018)

1. Research Methodology and
Evidence Based Healthcare (EBHC481)
LITERATURE REVIEW
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Lecture 9
Level 8
Year 4

2. Research Methodology and
Evidence Based Healthcare (EBHC481)
Objectives
• Define literature review
• Explain aim of literature review
• Describe of good characteristics of literature review
• Discuss steps of a literature review
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3. Research Methodology and
Evidence Based Healthcare (EBHC481)
I- Definition of a literature review
• Research literature review is a systematic, precise, critical method
for reading, analyzing, evaluating and summarizing, the existing
body of completed and recorded work produced by researchers,
scholars, and practitioners .
• It is one of the most important early steps prior to initiating any
research study.
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4. Research Methodology and
Evidence Based Healthcare (EBHC481)
What LR is NOT?
• It is not just a descriptive list of the material available, or a set of summaries
• A literature review is more than the search for information, and goes beyond
being a descriptive annotated bibliography.
• The following is NOT a LR:
Annotated bibliography List in text format
Ibrahim , S. D. (1995). Outcomes of Intervention X on
Pregnant women, Soba Hospital." BMJ 2/3, 34-38.
This article discusses the effect of the intervention X on
pregnant women delivering in Soba Teaching Hospital.
It also discusses the implications for reducing factor Y
on these women.
IBRAHIM and BANNAGA (1965) conducted experiments
on pregnant women in STH, basing on the theoretical
investigation of X interaction complemented by type Y.
It showed that the numerical results were in
reasonable agreement with laboratory experimental
data."

5. Research Methodology and
Evidence Based Healthcare (EBHC481)
Why/When do we need LR?
• LR can help in finding, developing, and/or fine-tuning your RQ.
• Determine the nature/method of your research
Find Research questions
• What is not known/established?
• What is not well known?
• What was not well-studied?
• Cross-referencing
Define gaps & references
• Strengths & weaknesses
• Theoretical base
• Comparison of findings
• Critical appraisal
Establish relations

6. Research Methodology and
Evidence Based Healthcare (EBHC481)
II- The aim of a literature review
1. It helps the researcher understand the existing body of knowledge in
a specific medical field. Moreover, the researcher will be updated on
the most recent findings in that field.
2. It identifies areas of consensus and debate among different studies,
and highlights the gaps in knowledge that exist in the literature,
which in turn justifies carrying out the research project.
3. It provides details of different research methodology that were
adopted by different researchers, which in turn helps in adopting the
most appropriate study methodology in the proposed study.
4. It identifies other researchers who share the same research interests,
who might act as support for future queries.
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7. Research Methodology and
Evidence Based Healthcare (EBHC481)
III- Characteristics of a good literature review
A good review should have the following characteristics which make it of value:
1- Comprehensive: Evidence should be gathered from all relevant sources.
2-Referenced: Providing full references for reviewed papers.
3- Selective: Using appropriate search strategies to find the most important
evidence.
4- Relevant: Focusing on related studies.
5- Balanced: Providing objective evidence from papers with different findings.
6- Critical: Following valid scientific critical appraisal of the literature.
7- Analytical: Developing new ideas and understandings from the evidence.
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8. Research Methodology and
Evidence Based Healthcare (EBHC481)
Search Strategy
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9. Research Methodology and
Evidence Based Healthcare (EBHC481)
IV- Steps of a literature review
1- Develop a research question
• The first step is to define a specific research question, which identifies
the research or clinical problem the research is aiming to solve.
• For example, a sample research question is:
• What strategies can healthcare workers use to communicate
effectively with clients with a hearing disability?
• Evidence based practice proponents advice using four elements in
building the research question, specifically, the PICO (Patient,
Intervention, Comparison, and Outcome).
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10. Research Methodology and
Evidence Based Healthcare (EBHC481)
Steps of a literature review
2- Types of the sources used in a literature review
THREE TYPES:
i. Primary source: Is a direct description of a research study written
by a researcher who conducted the study.
ii. Secondary source: Is a review of studies summarizing and
providing new interpretations built from and often extending
beyond the original study.
iii. Tertiary source: Include perceptions, conclusions, opinions, and
interpretations that are informally shared.
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11. Research Methodology and
Evidence Based Healthcare (EBHC481)
Literature sources available
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12. Research Methodology and
Evidence Based Healthcare (EBHC481)
Where to search?
• Library (institutional,
professional,
organizational)
• Archives
• Reports
Offline
• Journals websites
• Publishers’ databases
• Institutional
databases
• Institutional libraries
Online

13. Research Methodology and
Evidence Based Healthcare (EBHC481)
Before going online… remember!
• The printed resources have almost always been thoroughly ‘peer-reviewed’, and
systematically catalogued and cross-referenced
• On the Internet "anything goes."
• Don't rely exclusively on Internet resources.
• Narrow your research topic before logging on.
• Before you start your search, think about what you're looking for, and if possible
formulate some very specific questions to direct and limit your search
• Know your subject directories and search engines.
• There are several high quality peer-reviewed subject directories containing links
selected by subject experts
• Keep a detailed record of sites you visit and the sites you use (Ctrl+H).
• Keeping track is necessary so that you can revisit the useful ones later, and also
put the required references in your paper.

14. Research Methodology and
Evidence Based Healthcare (EBHC481)
Steps of a literature review
3- Search engines used in a literature review
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Universal Resource Locator

15. Research Methodology and
Evidence Based Healthcare (EBHC481)
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16. Research Methodology and
Evidence Based Healthcare (EBHC481)
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17. Research Methodology and
Evidence Based Healthcare (EBHC481)
Steps of a literature review
4. Establish the keywords and search strategy
• To effectively conduct a search, keywords to be used in the search
need to be identified, which are mainly the PICO elements.
• Moreover, a specific search strategy using the Boolean operators
(AND, OR, and NOT) should be developed, which can be used to
combine the keywords and concept in a search.
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18. Research Methodology and
Evidence Based Healthcare (EBHC481)
Steps of a literature review
5. Conducting the search
• PubMed is the primary database for researchers in the fields of biochemistry,
molecular biology, and related life sciences. It comprises over 20 million
references to articles published in more than 5,200 current biomedical journals
from the United States and over 80 foreign countries.
• It was developed by the National Center for Biotechnology Information (NCBI)
at the National Library of Medicine (NLM). It is one of several databases under
NCBI‟s Entrez retrieval system (the text-based search and retrieval system used
at NCBI for all of the major databases, including PubMed, and many others).
• PubMed can be directly accessed at: http://pubmed.gov or the National
Library of Medicine's homepage: http://www.nlm.nih.gov.
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19. Research Methodology and
Evidence Based Healthcare (EBHC481)
The main screens of Pubmed
• The most important features in PubMed which a researcher needs
to be familiarized with are: the main page (including database
selection menu, search box, and advanced search link), the search
results page, and the My NCBI.
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20. Research Methodology and
Evidence Based Healthcare (EBHC481)
The main screens of Pubmed
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The main page includes a database selection menu, a search box, and
an advanced search link.

21. Research Methodology and
Evidence Based Healthcare (EBHC481)
Steps of a literature review
6. Choosing the material to be included in the literature review
• In narrowing the literature selection, more focused screening criteria are taken into
consideration, such as:
• Date of publication: e.g. only studies conducted between 2005 and 2012
• Participants or subjects: e.g. children 6 to 12 years of age
• Publication language: e.g. documents written in English
• Research design: e.g. clinical trials
• Authors: e.g. well-known author in a specific field
• Journal: e.g. high impact journal, such as New England Journal of Medicine
• Relevance: e.g. similar objectives addressed and methodologies adopted
• Country of origin: Are you looking for UK only based information? Most databases will
allow you to limit your search by country, such as; UK, US or Europe.
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22. Research Methodology and
Evidence Based Healthcare (EBHC481)
Practical tips
• Wildcards are a way of searching for alternative spellings of the same words, e.g.
organisation (organization in the US) and paediatric (pediatric in the US).
To use the wildcard feature, you just need to substitute the wildcard symbol, which is
often ? , to replace a missing letter. For example, you could search for 'organi?ation'
to capture both "organization" and "organisation".
• Truncation is a way to try and capture all relevant material by searching for words or
phrases which use the same root.
To use the truncation feature, you just need to put the truncation symbol, which is
often either $ or * at the root of a word. For example: If you were looking for
information on "elderly people" you could use elder$ as this would bring up; elder,
elderly, elderly people
• Note: Use truncation with caution as it can sometimes bring up irrelevant results. For
example a search on commission$ would bring up references on commissioning but
also references on the "Commission for health improvement".
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23. Research Methodology and
Evidence Based Healthcare (EBHC481)
Practical tips: Boolean operators
• After identifying all the keywords, synonyms and phrases within a search, use the Boolean operators
'AND', 'OR' and 'NOT' to combine your topics areas together.
• Using OR
You can combine all the individual synonym searches together into one search using the OR operator
For example:
'old$' OR 'age$' OR 'elderly' OR 'geriatric$'
The OR operator broadens your results by including references that have ANY ONE of the search terms
within it.
• Using AND
You can focus the search by combining searches using the AND operator.
For example: {'old$' OR 'aged' OR 'geratric$'} AND {'care home$' OR 'residential home$' OR 'residential
care$' }
This search will find references that contain ALL of the three sets of synonyms.
• Using NOT
You can eliminate items from the search further using NOT
For example: {'old$' OR 'aged' OR 'geratric$'} AND {'care home$' OR 'residential home$' OR 'residential
care$'} NOT {'United States' OR 'US' OR 'USA'}
This will remove all references relating to the USA from your results.
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24. Research Methodology and
Evidence Based Healthcare (EBHC481)
Steps of a literature review
7.Critically analyze and evaluate the information
• Critical analyses of the chosen documents refer to the process of looking at
each document closely, reading the introduction, methodology, results and
discussion sections.
• As for the critical evaluation of the document, it refers to assessing the
validity of the methodology adopted, and relevance of the results reported.
• Biases affecting each of the documents should be taken into consideration,
and evaluated accordingly.
• Finally, integrate the reported results into the scope of the proposed
research.
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25. Research Methodology and
Evidence Based Healthcare (EBHC481)
Steps of a literature review
8. Cite literature properly
• There are four main reasons why it is important to cite literature
properly:
• To acknowledge the author(s) of the work that the researcher used.
• To provide context to the research and demonstrate that the research
is well-supported.
• To allow readers to find the original source and learn more about
some aspects mentioned in the document.
• Avoid plagiarism, which occurs when a writer deliberately uses
someone else's language, ideas, or other original material without
acknowledging its source.
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26. Research Methodology and
Evidence Based Healthcare (EBHC481)
V- Conclusion
• An effective review will increase likelihood of funding, generate
new ideas and directions for investigation, and improve the quality
of peer reviewed publication of primary research.
• At all stages of the process it is vital that the search process is
evaluated, since the inability to find relevant information can be
attributed to a poorly constructed search strategy, inappropriate
search terms, poor retrieval methods or inappropriate source.
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27. Research Methodology and
Evidence Based Healthcare (EBHC481)
Grey Literature
• Work that has not been published in
conventional books and journals.
• This includes reports, working papers,
theses and dissertations, newsletters,
many official and governmental
publications, and conference papers.
• Gray Literature includes:
• hard to find studies, reports, or
dissertations
• conference abstracts or papers
• governmental or private sector
research
• clinical trials - ongoing or
unpublished
• experts and researchers in the field
The AACODS checklist for appraisal of
GL
Main Sources
A Authority: Is the author credible? • WorldCat
A Accuracy: Is it supported
by documented and
authoritative references? Is there a
clearly stated methodology?
• Google Scholar
C Coverage: Have limitations been
imposed and are these stated clearly?
• World Health
Organization
O Objectivity: Can bias be detected? • Gray Source Index
D Date: Can't find the date? Rule of
the thumb is to avoid such material
Professional association
websites
S Significance: Is it relevant? Would it
enrich or have an impact on your
research?
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28. Research Methodology and
Evidence Based Healthcare (EBHC481)
Let’s go online!
Task:
In your laptops/computers, use the University of
Birmingham literature search strategy form to
conduct an online search of literature in your relevant
area of research.

29. Research Methodology and
Evidence Based Healthcare (EBHC481)
REFERANCE BOOK
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INTRODUCTION TO CLINICAL RESEARCH
FOR RESIDENTS, Hani Tamim, PhD
Saudi Commission for Health Specialties, 2014
Liverpool Hope University Doing a literature search: a step by step
guide. URL:
http://www.hope.ac.uk/media/liverpoolhope/contentassets/docum
ents/library/help/media,1256,en.pdf
Other helpful guides can be found on the following links:
https://becker.wustl.edu/sites/default/files/RespLitSearch.pdf
http://www.birmingham.ac.uk/facilities/hsmc-library/faqs/literature-
searching.aspx