Undertaking a literature review: a step'by-step approacii Patricia Cronin, Frances Ryan, Michael Coughian research literature on the topic being studied (Hart, 1998). Its goal is to bring the reader up-to-date with current Abstract hterature on a topic and form the basis for another goal, such Nowadays, most nurses, pre- and post-qualification, will be required as the justification for future research in the area. A good literature review gathers information about a particular to undertake a literature review at some point, either as part of a subject from many sources. It is well written and contains course of study, as a key step in the research process, or as part of few if any personal biases. It should contain a clear search clinical practice development or policy. For student nurses and novice and selection strategy (Carnwell and Daly, 2001). Good researchers it is often seen as a diflScult undertaking. It demands a structuring is essential to enhance the flow and readability complex range of skills, such as learning how to define topics for ofthe review. Accurate use of terminology is important and exploration, acquiring skiUs of literature searching and retrieval, jargon should be kept to a minimum. Referencing should developing the ability to analyse and synthesize data as well as be accurate throughout (Colhng, 2003). becoming adept at writing and reporting, often within a limited time scale. The purpose of this article is to present a step-by-step guide Types of literature reviews to facilitate understanding by presenting the critical elements of the Traditional or narrative literature review literature review process. While reference is made to diflFerent types of This type of review critiques and summarizes a body of literature reviews, the focus is on the traditional or narrative review literature and draws conclusions about the topic in question. that is undertaken, usually either as an academic assignment or part The body of literature is made up of the relevant studies of the research process. and knowledge that address the subject area. It is typically selective in the material it uses, although the criteria for Key words: Aneilysis and synthesis • Literature review • Literature selecting specific sources for review are not always apparent searching • Writing a review to the reader. This type of review is useful in gathering together a volume of literature in a specific subject area and summarizing and synthesizing it. he reasons for undertaking a literature review are Its primary purpose is to provide the reader with numerous and include eliciting information for a comprehensive background for understanding current developing policies and evidence-based care, a step knowledge and highlighting the significance of new in the research process and as part of an academic research. It can inspire research ideas by identifying gaps Tassessment. To many qualified nurses and nursing students or inconsistencies in a body of knowledge, thus helping faced with undertaking a literature review the task appears the researcher to determine or define research questions or daunting. Frequently-asked questions range from where hypotheses. Beecroft et al (2006) argue that a sufficiently to start, how to select a subject, and how many articles to focused research question is essential before undertaking include, to what is involved in a review of the literature. a literature review. Equally, however, it can help refine or The aim of this article is to present a step-by-step approach focus a broad research question and is useful for both topic to undertaking a review ofthe literature to facilitate student selection and topic refinement. It can also be helpful in nurses' and novice reviewers' understanding. developing conceptual or theoretical frameworks (Coughian What is a literature review? A literature review is an objective, thorough summary and Table 1. Non-research reasons for critical analysis of the relevant available research and non- undertaking a literature review •As an assignment for an academic course Patricia Cronin, Frances Ryan and Michael Coughian are Lecturers, •To update current personai knowledge and practice on a topic School of Nursing and Midwifery, University of Dublin, Trinity •To evaluate current practices College, Dublin •To develop and update guidelines for practice •To develop work-related policies Accepted for publication: November 2007 From: Polit and Beck (2006) 38 Britishjournal of Nursing. 2008, Vol 17. No 1 RESEARCH METHODOLOGIES et al, 2007). In addition, literature reviews can be undertaken independently of a research study (PoUt and Beck, 2006). Table 2. The literature review process Some reasons for this are described in Table 1. • Selecting a review topic Systematic literature review • Searching the literature In contrast to the traditional or narrative review, systematic • Gathering, reading and analysing the literature reviews use a more rigorous and well-defined approach to • Writing the review reviewing the literature in a specific subject area. Systematic • References reviews are used to answer well-focused questions about clinical practice. literature {Table 2). The first step involves identifying the i^irahoo (2006) suggests that a systematic review should subject ofthe literature review. The researcher undertaking detail the time frame within which the literature was, a quantitative study may have decided this already. However, selected, as well as the methods used to evaluate and for the individual undertaking a non-research based synthesize findings of the studies in question. In order for literature review this will be the first step. the reader to assess the reliability and validity of the review, the reviewer needs to present the precise criteria used to: Selecting a review topic • Formulate the research question Selecting a review topic can be a daunting task for students • Set inclusion or exclusion criteria and novice reviewers (Timmins and McCabe, 2005). A • Select and access the literature common error for novices is to select a review title that is • Assess the quality of the literature included in the all encompassing, such as 'pressure ulcers' or'pain'. Although review this may be a useful initial strategy for determining how • Analyse, synthesize and disseminate the findings. much literature is available, subjects such as these generate Unlike traditional reviews, the purpose of a systematic a considerable amount of data making a review infeasible. review is to provide as complete a list as possible of all the Therefore, it is advisable to refine this further so that the published and unpublished studies relating to a particular final amount of information generated is manageable. For subject area.While traditional reviews attempt to summarize example, to focus the topic of interest, consider what aspects results of a number of studies, systematic reviews use of pressure ulcers or pain are of particular significance. Is explicit and rigorous criteria to identify, critically evaluate there a specific element of this topic that is of interest, such and synthesize ail the literature on a particular topic. as prevention or management? Identifying what exactly is of interest and why can help refine the topic (Hendry and Meta-analysis Farley, 1998). Talking to others, such as clinical specialists, Meta-analysis is the process of taking a large body of or reading around a topic can also help to identify what quantitative findings and conducting statistical analysis in areas of the subject the reviewer is interested in and may order to integrate those findings and enhance understanding. help indicate how much information exists on the topic Meta-analysis is seen as a form of systematic review which is (Timmins and McCabe, 2005). largely a statistical technique. It involves taking the findings Having sufficient literature is also important, particularly from several studies on the same subject and analysing them when the review is an academic assignment. These using standardized statistical procedures. This helps to draw academic exercises usually have short deadlines, so having conclusions and detect patterns and relationships between enough literature is key from the perspective of being able findings (Polit and Beck, 2006). to do the review and submit it on time. Attempting to change the topic close to the deadline for submission is Meta-syn thesis usually a recipe for disaster so select an area that will hold Meta-synthesis is the non-statistical technique used to your interest and ensure that there is enough data to meet integrate, evaluate and interpret the findings of multiple your needs. qualitative research studies. Such studies may be combined to Literature reviews that are part of academic coursework identify their common core elements and themes. Findings usually have strictly enforced word limits and it is important from phenomenological, grounded theory or ethnographic to adhere to that limit. Topics that are too broad will result studies may be integrated and used. Unhke meta-analysis, in reviews that are either too long or too superficial. As a where the ultimate intention is to reduce findings, meta- rule of thumb, it is better to start with a narrow and focused synthesis involves analysing and synthesizing key elements topic, and if necessary broaden the scope of the review in each study, with the aim of transforming individual as you progress. It is much more difficult to cut content findings into new conceptualizations and interpretations successfully,