According to W.R. Borg “The literature of any field forms the foundation upon which all future will be built. If we fail to build the foundation of knowledge provided by the review of literature our work is likely to be shallow and naïve and will often duplicate work that has already been done better by someone else”

1. Literature Review in
Research
Prof. (Dr.) Sandeep Kumar Gupta MD
Professor and Head,
Department of Pharmacology,
HIMS, Varanasi

2. What is RESEARCH ?????
• Re ---------------- Search
• Re means (once more, afresh, anew) OR (back; with
return to a previous state)
• Search means (look thorough or go over thoroughly to look
for something) OR (examine to find anything concealed)
Research is an Scientific and SYSTEMATIC way of FINDING ANSWERS to QUESTIONS

3. Scientific research must follow a step by step
approach
• Research is known to be a
systematic study that follows
– a definite set of procedures and steps.
• It is crucial to follow
– definite set of steps when conducting
one’s research

4. Three stages at which a review of the
literature is needed
Plan
Research
Write
1. An early review
2. Review during the
period of your
research.
3. Review at the stage
of preparing your final
report
Introduction
Method
Result
Discussion
ROLi

5. A process as well as an outcome!
• A literature review is a process as well as an outcome!
• Literature review as a process: critical analysis of relevant
research on your topic.
• It is a crucial and formative stage of your thesis journey.
• Literature review as an outcome: appears in the final draft of
your thesis
• as part of your introduction or as a separate chapter.
The literature review begin before a research problem is finalized and continues until the report in finished.

6. What is Literature Review?

7. Unlike other animals that must start a new with each generation,
– Man builds upon the accumulated and recorded knowledge of the past.
• Man is the only animal that can take advantage of knowledge
– which has been preserved or accumulated through the centuries.
– Practically all human knowledge can be found in books and libraries
• His constant adding to the vast store knowledge
– makes possible progress in all areas of human endeavour.
• Human knowledge has three phases: preservation, transmission and advancement.
According to W.R. Borg

8. Literature
Definition - Literature (research)
“... a collection of all scholarly writing on a topic”.
These writing can be in the form of scholarly
Peer reviewed articles
Conference proceedings
Dissertations
Books,
And other sources alike
Preferably the literature which has been through a peer review process

9. A primary source is
a firsthand report of
research results
written by the
individual( s) who
actually conducted
the research
A secondary
source is a
description or
summary of
another person’s
work written by
someone who did
not participate in
the research
Compendia of
research
findings from
primary or
secondary
sources e.g.
textbook or
reference
volumes
These different categories represent the flow of information from the original sources.
Information generally flows from primary to secondary to tertiary sources.
Flow of
information
Flow of
information
The literature sources can be broadly categorized into three, viz., primary
(published and unpublished), secondary and tertiary.

10. The literature sources
• Primary – original research
Experimental (an intervention is
made or variables are
manipulated)
• Randomized Controlled Trials
• Controlled trials
Observational (no intervention or
variables are manipulated)
• Cohort studies
• Case-control studies
• Case reports
• Secondary – reviews of original
research
Meta-analysis
Systematic reviews
Practice guidelines
Reviews
Decision analysis
Consensus reports
Editorial, commentary
A secondary source can provide different ways of looking at an issue
or problem
But Secondary sources should not be overused

11. Literature search should be
started with:
A. Primary data
B. Secondary data
C. Tertiary data
D. Some other data
Best way: Start with Secondary sources and
then choose a few primary sources for
more details and a more specific research
question.
Easy way: Start with a primary article to
easily come up with a tentative research
question and then search the literature to
come up with specific questions.

12. What is Review?
Bloom’s Taxomony: Cognitive Domain (1956) as revised by Anderson & Krathwohl (2001)

13. Critical appraisal and synthesis of information
A. Summarize
C. Synthesize
[means to combine separate elements from several
sources on the same question/research topic to form a
whole and connect different authors]
B. Analysis and Evaluation
[means to assess the state of existing knowledge on a topic
by comparing and contrasting studies and by doing critical
appraisal of their strength and weaknesses ]
Compose the writing:
Present A, B, C then relate to your current study
(appropriate referencing)

14. 5C of literature review
Critique
Compare
Contrast
Combine
Connect
5C

15. Avoid Plagiarism
• DO NOT copy and paste ANYTHING!
• If you are using anyone else’s ideas,
– they need to be in your words or in quotation
– author must ALWAYS get cited in your
reference
• ALWAYS CITE source

16. Promotes Critical Thinking…
Move from Description to Analysis!
Description – reproducing information
• Summarising texts - accepting details, results etc.
Analysis – deconstructing information to:
• Challenge assumptions; perspectives
• Show limitations in studies, exceptions to cases
• Highlight under-examined aspects of research
Literature Review….
Your literature review, when completed
should provide you with a clear picture of
what you will do and how you will do it

17. A literature review is NOT . . .

18. A literature review is not an annotated bibliography in which you
summarize briefly each article that you have reviewed
Annotated bibliography
=
precursor to a
literature review
Literature
review
=
foundation for
one’s research
A summary of the what you have read is
contained within the Annotated
Bibliography,
Literature review goes well beyond
merely summarizing literature.
Critical analysis and evaluation of
specific topic of interest
A synthesis of the relationship
among different works

19. The Literature Review…
IS NOT
• A summary of existing
literature
• An annotated
bibliography
• A list of seemingly
unrelated sources
• An argument about the
importance of your
research
• Simply a description of
what others have
published
IS
• An analysis of the state of existing
knowledge on a topic by comparing
studies
• An evaluation of the strength and
weaknesses of previous research
• Synthesis of the relationship among
different works
• A synthesis of studies on any given
topic
• A critical analysis of a specific topic
of interest

20. Purpose of Literature Review

21. Standing on the shoulders of giants
• Review of literature is
– like standing on the
shoulder of the giants
(previous scholars).
• It is not only to see
what they have done,
– but it is to visualize
beyond their visions

22. New research grows out of old
According to W.R. Borg
“The literature of any field forms the
foundation upon which all future will be
built.”
• If we fail to build the foundation of
knowledge provided by the review of
literature our work is likely to be shallow
and naïve and
• We will often duplicate the work that
has already been done better by
someone else”
We can learn from and build on what others have done
Your study should be a logical extension of past
research
Each research study
is part of an existing
body of knowledge

23. Find research gap from
previous research or
• certain areas that have not
been studied fully
You need to find out
• what is missing from the
previous studies
• to explain what your study
intends to do to fill the gap
Purpose of Literature Review

24. Research is like building a skyscraper
You have to establish yourself on something existing.
• Establish what is already known about a particular topic and
• Prevents oneself from reproducing what is already known
• Exposes gaps in the literature and helps you position your research
• Point the way in fulfilling a need for additional research
• Locate your own research within the context of existing literature
• Help to identify new areas where research is needed
There is no point of reinventing the wheel!

25. The Literature Review Process

26. 1. Develop
the research
question
2. Identify
the Keywords
3. Identify
the relevant
literature
source
4. Search the
literature
5. Analysing
and
synthesizing
the literature
6. Write the
literature
review
Literature Review
Process

27. 1. DEVELOPING YOUR RESEARCH QUESTION
• In order to begin your literature review, you must first
define your research question
• Creating a structured research question: PICO(S)
• Populations
• Interventions (or exposure)
• Comparators
• Outcomes
• Study design

28. 2. Identifying the key research terms
(Keywords)
• The keyword is the basic unit of any search
• Compiling a list of keywords
• Think about both general terms and very specific terms for broadening and
narrowing your search
• The use of index and/or thesaurus is also advisable to establish the
useful terms

29. 3. Identifying the relevant sources
Traditional paper sources
(searched manually)
Electronic sources:
Searched using computer

30. 4. Search the literature
• Library
– Books, journals,
conference souvenir
and conference
proceedings
• Electronic Resources
– Journals : The Lancet, BMJ,
Indian Pediatrics etc.
– Databases : PubMed, Embase,
Science direct etc.
A database is an organized collection of data.

31. • Disorganization
• Validity of information
• Outdated websites
• Lack of peer reviewed studies

32. • Google Scholar
http://scholar.google.com/
• NLM Medline
http://www.nlm.nih.gov/pubs/factsheets/medline.html
• PubMed
http://pubmed.gov/
• PubMed Central
http://www.ncbi.nlm.nih.gov/pmc/
• The Cochrane Library
https://www.cochranelibrary.com/
• ScienceDirect
https://www.sciencedirect.com/
• IndMed
http://indmed.nic.in/
• Embase
https://www.elsevier.com/solutions/embase-biomedical-
research
Access to Biomedical Database

33. Google-Scholar
 Many articles look out-
of-place compared to
my intented meaning
 However, some of
them do look what I
actually meant
 What else I see ?
 Related articles
 Cited by

34. What is MEDLINE?
• MEDLINE is the bibliographic database produced by the
National Library of Medicine (USA)
• It contains over 24 million references to journal articles
• Gathered from 4,600 biomedical journals published in the United States and
in 70 other countries
• Dating back to 1950, with daily updates
• Electronic version of Index Medicus, Index to Dental Literature, and the
International Nursing Index.

35. Different routes to MEDLINE
• The free one
• PubMed: www.pubmed.gov

36. PubMed – Homepage

37. Why we choose PubMed?
• Freely available on the web
• URL easy to remember
• Quick and easy to search
• For very recent articles
• Clinical Queries
– Search by Clinical Study Category
• Links to publisher’s sites for full-text journals
– Or, can order full-text journal articles

38. PubMed – Additional Tools
• Boolean Statements
– AND, OR, NOT
• MeSH
– Stands for Medical Subject Headings
– “controlled vocabulary list” of PubMed with more
than 25,000 subject headings.
– Used for indexing biomedical literature
– 10-15 MeSH are assigned to each article
in PubMed

39. BOOLEAN OPERATORS
• AND (narrows the search by retrieving only records
containing both keywords used in the search statement)
• OR (broadens your search by retrieving either one or
more of the keywords used in the search statement)
• NOT (excludes records containing the second keyword
in your search statement)

40. PERFORMING THE SEARCH – SEARCH TERMS
AND Diabetes AND hypertension
OR Diabetes OR hypertension
NOT Diabetes NOT hypertension

41. Review Of Literature
Tertiary
Secondary
Primary
• Not only racking up points
by listing as many articles
as possible
• Recognize relevant
information, and
synthesize and evaluate it
• Your reader not only
wants to know what
literature exists, but also
your informed evaluation
of the literature.
5. Analysing and synthesizing the literature

42. 6. Writing the literature review
“Bad research but good writing may still convince readers;
Good research but bad writing will never convince readers”
Unknown author
Critical Reading = Critical Writing

43. The narrative of a good literature review
General-to-Specific Order—(Also called the Funnel approach)
Reader
knows
Reader
doesn't
know
Introduce the
field: broad
focus
End with gap
analysis
Hypothesis
Focus on specific
studies related to
the topic

44. Gives a quick idea
of the topic of the
literature review,
such as the central
theme
Contains your
discussion of
sources
Conclude what you
have drawn from
reviewing literature

45. 5 minute Post test
Read the following statements and identify if they are true (T) or false (F).
1. T / F A literature review do not prevents duplication of work
2. T / F A literature review should always identify a need for
further research.
3. T / F The order of literature review should be general to specific.
4. T / F A research question is important to guide research for a
literature review.
5. T / F The keyword is the basic unit of any search.
6. T / F Literature review do not promotes critical thinking.

46. Answer key
1 ---- F
2 ---- T
3 ---- T
4 ---- T
5 ---- T
6 ---- F