Transcript Roberta Sammut - Lecture Literature Review

The Literature Review in
the Masters Dissertation
Roberta Sammut
The role of research reviews
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What is research?
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‘The systematic investigation to develop theories, establish
evidence and solve problems’ (Gough et al 2012 p.1)
Research can focus on:
 The creation of new knowledge through primary studies
 Creation of knowledge on the basis of previous research
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Knowledge should be cumulative (Oakley 2012)
‘If I have seen further it
is by standing on the
shoulders of giants’ –
Isaac Newton
Why are reviews needed
‘Research information is like small
jigsaw puzzle pieces in a box,
where there are several
pictures, several duplicates
and several missing pieces’
(Sheldon 1998)
Individual studies use different
methods, are of different
quality and may present
contradictory findings
We cannot give too much
importance to one individual
study
Why do you need to carry out
a literature review?
Needed for identifying:
 Areas of uncertainty
 Where reality may be different
to what is believed
 Where more research is
needed
 How research in the area has
been carried out – strengths
and limitations
 The main theories and issues
on your topic and critique of
these
What distinguishes a good
quality literature review?
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Appropriate breadth and depth
Rigour and consistency
Clarity and brevity
Effective analysis and synthesis
Use of the literature to justify:
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The particular approach to the topic
The selection of methods
That your research contributes something new
Changing expectations at a
postgraduate level
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What is expected of a literature review at
undergraduate level
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Familiarity with a topic
Skills to be able to carry out a search on the
subject
Knowledge on appropriate referencing style and
an ability to create accurate bibliography
The ability to summarise key ideas and some
critical awareness
Changing expectations at a
postgraduate level (Hart 2007)
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The content of the literature review at
undergraduate level
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Descriptive and focused on the topic
Includes the main current papers on the topic
Analyses the papers on the topic in terms of
different arguments presented and different
results
The expectations at Masters
level (Hart 2007)
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An increase in the scope, breadth and depth
of the literature search
Application of relevant literature from across
other disciplines
Competence in reading research
The literature review of the
Masters dissertation (Hart 2007)
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The literature review is a major component of your
dissertation
Analytical – evaluating current ideas on the topic
Summative – providing a comprehensive overview
of what is known, what the gaps are
Covers methodological issues in relation to different
research techniques
Includes discussion of theoretical issues relevant to
the study
Your literature review in
context
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Your thesis must form a coherent whole
Your literature review should be clearly linked
to:
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Your justification for carrying out the study
Your aims and objectives
Your choice of research design
The methods used to collect data
Your discussion of the results
Your conclusions and recommendations
Starting out: what type of review
is appropriate to your work?
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Traditional Review (Gough 2004)
Journalistic Review (Greenhalgh 1997)
Narrative Review (Macdonald 2003)
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Usually broader in focus
Do not address specific question
Not necessarily comprehensive in literature included
Do not state reasons for inclusion of papers
Not structured in approach to searching for literature and
evaluation of quality
Systematic Review
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‘the shift in emphasis from the art of writing a review to the
science of reviewing the evidence’ (Milne and Chambers 1993)
Famous example of possible
different outcomes for systematic
vs. traditional reviews (Petticrew and
Roberts 2006)
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Linus Pauling (1974) Well-known physician
and Nobel prize laureate
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Carried out review on effect of Vitamin C on
prevention of colds
Conclusions:
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High dose of Vit C prevents colds
People should consume 100 times dose of Vitamin C
than currently being consumed
Famous example of possible
different outcomes for systematic
vs. traditional reviews (Petticrew and
Roberts 2006)
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Douglas et al (2004)
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Systematic review of papers published during the
time of Pauling’s review
Conclusions:
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High doses of Vitamin C do not prevent colds
Can reduce the duration of the cold by a few days
Pauling did not include 15 relevant articles
What is a systematic review?
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‘A review of research literature using systematic
and explicit, accountable methods’ (Gough 2012)
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The key characteristics of a systematic review are:
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Rigor: use of systematic methods to answer set research
question
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Transparency: every step is described; nothing left to
reader’s imagination
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Replicability: a second researcher should arrive at the
same conclusions
(Oakley 2012)
Features of systematic
reviews: Rigor (Oakley 2012)
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The methods used are designed to ensure rigor in
the process being used and are predetermined
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Comprehensiveness in the search used to avoid excluding
relevant research e.g. grey literature which could lead to
publication bias
Specific criteria for the inclusion or exclusion of studies – to
avoid leaving out unfavourable results
Use of more than one researcher to search literature,
decide on inclusion and exclusion of studies, appraise
studies
Conclusions are based on the most rigorous studies
Features of systematic reviews:
Transparency (Oakley 2012)
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Systematic reviews must be clear about:
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The question the review is designed to answer
The suitability of the methods chosen
How the studies were identified
Why some studies were included and others not
How judgements were made about the value of
particular studies in answering the research
questions
The conclusions which are reached in relation to
policy and practice
Features of systematic reviews:
Replicability (Oakley 2012)
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A systematic review should provide a clear
explanation of all steps taken in the review
process
This should allow another researcher to
repeat the study
If the review was carried out rigorously, then
the results of the second review should be
the same
Because procedures used are described, the
review can be updated
Diversity of systematic
reviews
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A systematic review is a secondary research
study
Questions and methods used in systematic
reviews reflect those of the primary research
studies
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Share the same theoretical assumptions
Share the same approach
The key steps of a systematic
review (Gough 2012)
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Review initiation: Formation of review team; engagement of
stakeholders
Preparation of a protocol: review question, conceptual framework
and methodology
Search strategy: search and screen literature on the basis of
eligibility criteria
Mapping: identifying and describing relevant research papers
Appraising: critically critiquing the research papers using
systematic methods (quality appraisal criteria)
Synthesis: Putting together the results of the review into a
coherent whole, creating something new (using conceptual
framework and quality judgements)
Using reviews (interpret and communicate findings with
stakeholders)
All decisions/methods used are explained and justified
One species; many breeds
Systematic reviews may differ on the basis
of the:
 Nature of the research question (Oakley
2012)
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What we want to find out:
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What works
What people want
What people consider to be appropriate
The breadth and depth of the research
question
E.g. ‘What is known about the barriers to
and facilitators of healthy eating and
physical activity in young people?’ vs.
‘Is CBT more effective than Health
Education in producing weight loss in
young people between 14 and 16 years of
age?
Step 2: develop a search
strategy
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Clearly identify your review question
PICO framework:
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Population (P),
Intervention (I) or Exposure (E),
Comparison (C),
Outcomes (O),
Time (T)
SPICE framework:
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Setting – where?
Perspective – for whom?
Intervention – what?
Comparison – compared with what?
Evaluation – with what result?
Step 2: Develop a search
strategy
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Identify the relevant databases: e.g. CINAHL,
MedLine, PsychInfo, AgeLine etc.
Consider the advantages/disadvantages of running
combined searches
Identify the keywords which you should use to
access relevant research papers – use thesaurus,
MeSH terms
Plan out Boolean phrases, truncation and wild cards
Identify any limiters to your search – with justification
Step 3: Develop
inclusion/exclusion criteria
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Your review should not include every
possible paper on your topic
The papers you include should be directly
relevant
Develop inclusion/exclusion criteria on the
basis of your review question
Step 4: Develop review
management tools
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Keep track of what you are doing on a daily
basis: use a diary
Use bibliographic software/files on
databases/excel sheets to keep track of
articles you exclude with reasons for
exclusion
Develop an information extraction sheet to
consistently extract the same type of data
from each paper
Step 5: Use the PRISMA
flowchart
Identification
PRISMA 2009 Flow Diagram
Records identified through
database searching
(n = )
Additional records identified
through other sources
(n = )
Eligibility
Screening
Records after duplicates removed
(n = )
Records screened
(n = )
Records excluded
(n = )
Full-text articles assessed
for eligibility
(n = )
Full-text articles excluded,
with reasons
(n = )
Included
Studies included in
qualitative synthesis
(n = )
Studies included in
quantitative synthesis
(meta-analysis)
(n = )
Step 6: Appraise your studies
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Weight of evidence framework (Gough 2007).
Three dimensions:
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Quality of execution of the study ‘soundness’
Appropriateness of the study design and analysis
for addressing the research question
How well matched the study is to the focus of the
review
Step 6: Appraise your studies
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Use a Checklist or scale to systematically examine main
methodological aspects of each study
Less likely that methodological problems will be missed
More than one checklist may be needed if mixed methods are used
Multitude of appraisal tools available:
 Downs and Black – randomized and nonrandomized studies
 Cowley – comparative studies
 Newcastle-Ottawa Scale – nonrandomised studies
 Critical Appraisal Skills Programme
There may not be a suitable checklist available – you may need to
adapt a checklist or develop a new one
Step 6: Appraise your studies
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When choosing an appraisal tool consider:
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Checklist chosen must be suitable for design of
studies to be included in the review
Whether the appraisal tool has been previously
tested or not for validity and reliability
You may need to use more than one appraisal
tools if mixed methods are included
Step 7: Decide on how you are
going to use the information from
the appraisal
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As a threshold to include/exclude studies
‘Weight’ the studies qualitatively, when summarizing the
results e.g. high, intermediate, low quality
‘Weight’ the studies quantitatively - low scoring studies
contribute less to the final summary effect size estimate
Describe the quality and relevance of each study for the
reader to arrive at own conclusions
Carry out a sensitivity analysis – effect of
including/excluding studies of lower quality on the results
Recommendations for future research in terms of
methods
Step 7: Writing up
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Prepare a plan of your review
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Introduction
History of the topic – including assumptions and definitions
from other researchers
Theoretical background
Address each of your research objectives by summarising
research
Conclusion
Identify how the data you extracted will be
synthesised:
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Meta analysis
Narrative synthesis
Questions to ask yourself when writing up (Hart 2007, p. 14)
What are the
key theories,
concepts and
ideas?
What are the
key sources?
What are the
major issues
and debates
about the
topic?
Literature
search and
review on your
topic
What are the
political
standpoints?
What are the
origins and
definitions of
the topic?
What are the
epistemologica
l and
ontological
grounds for the
discipline?
What are the
main questions
and problems
that have been
addressed to
date?
How is
knowledge on
the topic
structured and
organised?
How have
approaches to these
questions increased
our understanding
and knowledge?
In summary: key issues for
success
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Perseverance and diligence!
Justification for the topic of your research and your choice of
approach
Avoid communicating personal opinions and views and don’t
present facts without sufficient evidence
Learn how to reference properly – invest in a training programme
on the use of bibliographic software
Learn how to use search databases
Befriend your librarian!
Keep records of your ongoing work to prevent panic later on!
Be charitable to others’ work whilst at the same time evaluating it!
Remember – there is no such thing as a perfect review!
Recommended Reading List
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Bettany-Saltikov, J.B. (2012) How to do a systematic literature review in nursing.
Open University Press, England
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Gough, D., Olivers, S. and Thomas, J. (2012) An introduction to systematic
reviews. Sage, London
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Greenhalgh, T. (2010) 4th ed. How to read a paper Wiley-Blackwell, Oxford
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Hart C. (2007) Doing a literature review: releasing the social science research
imagination. Sage, London
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Hart C. (2001) Doing a literature search. Sage, London
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Petticrew, M. and Roberts H. (2006) Systematic reviews in the social sciences
Blackwell publishing, U.S.A.
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Rudestam, K.E. and Newton R.R. (2007) 3rd ed. Surviving your dissertation Sage,
London