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The Literature Review in the Masters Dissertation
Roberta Sammut
The role of research reviews
What is research? ‘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
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?
Appropriate breadth and depth Rigour and consistency Clarity and brevity Effective analysis and synthesis Use of the literature to justify:
The particular approach to the topic The selection of methods That your research contributes something new
Changing expectations at a postgraduate level
What is expected of a literature review at undergraduate level 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)
The content of the literature review at undergraduate level 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)
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)
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
Your thesis must form a coherent whole Your literature review should be clearly linked
to: 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?
Traditional Review (Gough 2004) Journalistic Review (Greenhalgh 1997) Narrative Review (Macdonald 2003)
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
‘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)
Linus Pauling (1974) Well-known physician and Nobel prize laureate Carried out review on effect of Vitamin C on
prevention of colds Conclusions:
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)
Douglas et al (2004) Systematic review of papers published during the
time of Pauling’s review Conclusions:
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?
‘A review of research literature using systematic and explicit, accountable methods’ (Gough 2012)
The key characteristics of a systematic review are: Rigor: use of systematic methods to answer set research
question Transparency: every step is described; nothing left to
reader’s imagination Replicability: a second researcher should arrive at the
same conclusions (Oakley 2012)
Features of systematic reviews: Rigor (Oakley 2012)
The methods used are designed to ensure rigor in the process being used and are predetermined 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)
Systematic reviews must be clear about: 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)
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
A systematic review is a secondary research study
Questions and methods used in systematic reviews reflect those of the primary research studies Share the same theoretical assumptions Share the same approach
The key steps of a systematic review (Gough 2012)
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 breedsSystematic reviews may differ on the basis
of the: Nature of the research question (Oakley
2012) What we want to find out:
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 Clearly identify your review question PICO framework:
Population (P), Intervention (I) or Exposure (E), Comparison (C), Outcomes (O), Time (T)
SPICE framework: Setting – where? Perspective – for whom? Intervention – what? Comparison – compared with what? Evaluation – with what result?
Step 2: Develop a search strategy
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
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
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
PRISMA 2009 Flow Diagram
Records identified through database searching
(n = )
Scre
enin
g In
clud
ed
Elig
ibili
ty
Iden
tifica
tion
Additional records identified through other sources
(n = )
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 = )
Studies included in qualitative synthesis
(n = )
Studies included in quantitative synthesis
(meta-analysis) (n = )
Step 6: Appraise your studies
Weight of evidence framework (Gough 2007). Three dimensions: 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 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
When choosing an appraisal tool consider: 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 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 Prepare a plan of your review
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: Meta analysis Narrative synthesis
What are the key sources?
What are the major issues and debates
about the topic?
What are the political
standpoints?What are the origins and
definitions of the topic?
How is knowledge on
the topic structured and
organised?
What are the main questions and problems
that have been addressed to
date?
What are the epistemologica
l and ontological
grounds for the discipline?
What are the key theories, concepts and
ideas?
Literature search and
review on your topic
Questions to ask yourself when writing up (Hart 2007, p. 14)
How have approaches to these questions increased our understanding and knowledge?
In summary: key issues for success 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 Bettany-Saltikov, J.B. (2012) How to do a systematic literature review in nursing.
Open University Press, England
Gough, D., Olivers, S. and Thomas, J. (2012) An introduction to systematic reviews. Sage, London
Greenhalgh, T. (2010) 4th ed. How to read a paper Wiley-Blackwell, Oxford
Hart C. (2007) Doing a literature review: releasing the social science research imagination. Sage, London
Hart C. (2001) Doing a literature search. Sage, London
Petticrew, M. and Roberts H. (2006) Systematic reviews in the social sciences Blackwell publishing, U.S.A.
Rudestam, K.E. and Newton R.R. (2007) 3rd ed. Surviving your dissertation Sage, London