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The Literature Review in the Masters Dissertation

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1 The Literature Review in the Masters Dissertation
Roberta Sammut

2 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) Knowledge should be cumulative: We should undertake research in a way that what we know is capable of being updated as circumstances, time and contexts changes and as new studies are done. Originally developed in the social sciences, but became famous for their use in healthcare. Logic of using systematic methods for bringing together relevant research evidence to inform decision-making Applies to all academic disciplines, all research questions, all research methods and all research data In health care they are best known for addressing qeustions about the effects of particular drugs or medical procedures In health and social science, reviews are increasingly being used to address other research questions and developing new review methods to do this.

3 ‘If I have seen further it is by standing on the shoulders of giants’ –
Isaac Newton Dwarfs standing on the shoulders of giants (Latin: nani gigantum humeris insidentes) is a Western metaphor with a contemporary interpretation meaning "One who develops future intellectual pursuits by understanding and building on the research and works created by notable thinkers of the past".

4 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 Under these circumstances it can eb difficult for the researche, researcher funder or user to make sense of the resarch or to take stock of the knowledge base Systematic reivew are a method of making sense of large bodies of information and a means of contributing to the answers to questions about what works and what does not – and many other type of questions Rely on reviews to help organise and prioritize the most relevant information

5 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 There are areas where we think we know much more than we do, but where in reality there is little convincing evidence to support our belief Real and assumed knowledge – systematic reviews can help us tell which is which

6 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

7 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

8 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

9 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

10 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

11 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

12 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) Most literature reviews carried out more than a decade ago were not done in a systematic way Reviewers did not necessarily attempt to identify all relevant research, check what is reliable or write up their results in an accountable manner Focus of previous reviews was on broad topic areas, rather than focused questions Systematic reviews are literature reviews that adhere closely to a set of scientific methods that explicitly aim to limit systematic error (bias), mainly by attempting to identify, appraise and synthesise all relevant studies (whatever design) in order to answer a particular Set out their methods in advance and in detail In many ways there are similar to a survey, a survey of research – another research method

13 Famous example of possible different outcomes for systematic vs
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

14 Famous example of possible different outcomes for systematic vs
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

15 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) Literature reviews may themselves be biased and by carefully selecting studies to review it is possible to produce two similar reviews that come to entirely opposite conclusions. Literature reviews even those written by experts can be made to tell any story one wants them to, and failure by literature reviewers to apply scientific principles to the proecess of reviewing the evidence, just as one would to primary research can lead to biased conclusions and to harm and wasted resources.

16 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

17 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

18 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

19 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 E.g. a systematic review that focuses on what works will look at interventional studies which usually involve an experimental design, will take a very structured approach to the review.

20 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

21 One species; many breeds
Systematic 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? There is a wide array of questions that can be addressed through social science research e.g. processes by which things happen, frequency, effects, concepts to understant these phenomena. Any question that we address using primary research methods can also be asked via the use of secondary research methods such as systematic reviews. Very narrowly specified questions in depth – richer analys Broader questions in less depth One way of providing depht is to undertake a set of reviews on the same topic. E.g. as happends with the Cocharne Collaboration. Series of reviews addressing related, but narrow questions

22 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?

23 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

24 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

25 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

26 Step 5: Use the PRISMA flowchart

27 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

28 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

29 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

30 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

31 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

32 Questions to ask yourself when writing up (Hart 2007, p. 14)
How have approaches to these questions increased our understanding and knowledge?

33 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!

34 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

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