Presentation on theme: "The Literature Review in the Masters Dissertation"— Presentation transcript:
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 studiesCreation of knowledge on the basis of previous researchKnowledge 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-makingApplies to all academic disciplines, all research questions, all research methods and all research dataIn health care they are best known for addressing qeustions about the effects of particular drugs or medical proceduresIn 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 NewtonDwarfs 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 findingsWe cannot give too much importance to one individual studyUnder 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 baseSystematic 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 questionsRely 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 uncertaintyWhere reality may be different to what is believedWhere more research is neededHow research in the area has been carried out – strengths and limitationsThe main theories and issues on your topic and critique of theseThere are areas where we think we know much more than we do, but where in reality there is little convincing evidence to support our beliefReal and assumed knowledge – systematic reviews can help us tell which is which
6 What distinguishes a good quality literature review? Appropriate breadth and depthRigour and consistencyClarity and brevityEffective analysis and synthesisUse of the literature to justify:The particular approach to the topicThe selection of methodsThat your research contributes something new
7 Changing expectations at a postgraduate level What is expected of a literature review at undergraduate levelFamiliarity with a topicSkills to be able to carry out a search on the subjectKnowledge on appropriate referencing style and an ability to create accurate bibliographyThe 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 levelDescriptive and focused on the topicIncludes the main current papers on the topicAnalyses 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 searchApplication of relevant literature from across other disciplinesCompetence in reading research
10 The literature review of the Masters dissertation (Hart 2007) The literature review is a major component of your dissertationAnalytical – evaluating current ideas on the topicSummative – providing a comprehensive overview of what is known, what the gaps areCovers methodological issues in relation to different research techniquesIncludes discussion of theoretical issues relevant to the study
11 Your literature review in context Your thesis must form a coherent wholeYour literature review should be clearly linked to:Your justification for carrying out the studyYour aims and objectivesYour choice of research designThe methods used to collect dataYour discussion of the resultsYour 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 focusDo not address specific questionNot necessarily comprehensive in literature includedDo not state reasons for inclusion of papersNot structured in approach to searching for literature and evaluation of qualitySystematic 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 wayReviewers did not necessarily attempt to identify all relevant research, check what is reliable or write up their results in an accountable mannerFocus of previous reviews was on broad topic areas, rather than focused questionsSystematic 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 particularSet out their methods in advance and in detailIn 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 laureateCarried out review on effect of Vitamin C on prevention of coldsConclusions:High dose of Vit C prevents coldsPeople 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 reviewConclusions:High doses of Vitamin C do not prevent coldsCan reduce the duration of the cold by a few daysPauling 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 questionTransparency: every step is described; nothing left to reader’s imaginationReplicability: 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 predeterminedComprehensiveness in the search used to avoid excluding relevant research e.g. grey literature which could lead to publication biasSpecific criteria for the inclusion or exclusion of studies – to avoid leaving out unfavourable resultsUse of more than one researcher to search literature, decide on inclusion and exclusion of studies, appraise studiesConclusions 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 answerThe suitability of the methods chosenHow the studies were identifiedWhy some studies were included and others notHow judgements were made about the value of particular studies in answering the research questionsThe 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 processThis should allow another researcher to repeat the studyIf the review was carried out rigorously, then the results of the second review should be the sameBecause procedures used are described, the review can be updated
19 Diversity of systematic reviews A systematic review is a secondary research studyQuestions and methods used in systematic reviews reflect those of the primary research studiesShare the same theoretical assumptionsShare the same approachE.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 stakeholdersPreparation of a protocol: review question, conceptual framework and methodologySearch strategy: search and screen literature on the basis of eligibility criteriaMapping: identifying and describing relevant research papersAppraising: 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 worksWhat people wantWhat people consider to be appropriateThe breadth and depth of the research questionE.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 analysBroader questions in less depthOne 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 questionPICO 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 searchesIdentify the keywords which you should use to access relevant research papers – use thesaurus, MeSH termsPlan out Boolean phrases, truncation and wild cardsIdentify any limiters to your search – with justification
24 Step 3: Develop inclusion/exclusion criteria Your review should not include every possible paper on your topicThe papers you include should be directly relevantDevelop 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 diaryUse bibliographic software/files on databases/excel sheets to keep track of articles you exclude with reasons for exclusionDevelop an information extraction sheet to consistently extract the same type of data from each paper
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 questionHow 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 studyLess likely that methodological problems will be missedMore than one checklist may be needed if mixed methods are usedMultitude of appraisal tools available:Downs and Black – randomized and nonrandomized studiesCowley – comparative studiesNewcastle-Ottawa Scale – nonrandomised studiesCritical Appraisal Skills ProgrammeThere 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 reviewWhether the appraisal tool has been previously tested or not for validity and reliabilityYou 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 estimateDescribe the quality and relevance of each study for the reader to arrive at own conclusionsCarry out a sensitivity analysis – effect of including/excluding studies of lower quality on the resultsRecommendations for future research in terms of methods
31 Step 7: Writing up Prepare a plan of your review IntroductionHistory of the topic – including assumptions and definitions from other researchersTheoretical backgroundAddress each of your research objectives by summarising researchConclusionIdentify how the data you extracted will be synthesised:Meta analysisNarrative 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 approachAvoid communicating personal opinions and views and don’t present facts without sufficient evidenceLearn how to reference properly – invest in a training programme on the use of bibliographic softwareLearn how to use search databasesBefriend 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, EnglandGough, D., Olivers, S. and Thomas, J. (2012) An introduction to systematic reviews. Sage, LondonGreenhalgh, T. (2010) 4th ed. How to read a paper Wiley-Blackwell, OxfordHart C. (2007) Doing a literature review: releasing the social science research imagination. Sage, LondonHart C. (2001) Doing a literature search. Sage, LondonPetticrew, 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