CHAPTER 5 Locating and appraising the evidence
5.2 Introduction
5.2.1 Why is it important to develop skills in locating and evaluating evidence?
The quality of patient care is of primary concern for nurses and for this reason nurses must base their care and decision making on the best available research evidence. Basing nursing care upon misunderstood, outdated or poor quality research findings may potentially lead to adverse outcomes for large numbers of patients (Carr 2006). Decision making by nurses may be guided by a range of factors such as habit, tradition, instructions from other staff, intuition, experience, trial and error, prior knowledge and education, patient preference, policy and guidelines, and direct application of research evidence (Craig 2007). While research evidence may also inform education, patient preference, instructions from other staff, policy and guidelines, it is just one component of the knowledge the nurse brings to the point of clinical decision making (Kitson 2007, Estabrooks et al 2003).
It is important to remember that evidence-based practice (EBP) ‘integrates clinical expertise and patient values with the best available research evidence’ (Sackett et al 2000:1), and is ‘a research-based, decision-making process utilised to guide the delivery of holistic patient care by nurses’ (Boswell & Cannon 2007:10).
One of the most critical tasks in EBP can be simply deciding where to start looking for the best available research evidence. Nursing students past and present will be familiar with the traditional paper-based printed resources—the nursing textbook, the professional journal or conference publication. While still important, and in some cases only available in print, these may not be the most useful resources for locating current research evidence due to the publication time lag (Dong et al 2006, Terio 2003). The huge growth in electronic publishing has meant the availability of the very latest, high-quality professional information and research, usually (but not always) available in full text and easily accessible via the internet. While finding information has never been so easy, finding the right information can be difficult and time consuming without some initial guidance. The information in Section 5.3 will help you to develop strategies for selecting the appropriate resources for locating the evidence you need, by introducing you to some of the key electronic nursing resources appropriate to your question or topic.
In summary, nurses must develop skills and strategies for locating and appropriately applying high-quality research evidence to practice. As discussed, a useful first step in this process is for nurses to recognise that they are already evaluating content and actively deciding to further develop their skills. The topics in this chapter present sequential and practical information aimed at helping nurses develop basic skills in accessing, appraising and understanding the best available research evidence. This will provide nurses with the best available evidence to bring to the decision-making process—evidence that can be incorporated with their own knowledge and experience in considering of the individuality of the patient. The challenge for the busy nurse is how to navigate the potential information overload and make sense of the information that is located. This chapter will discuss basic time-efficient strategies for the location and evaluation of research evidence while also offering direction and guidance for the development of advanced appraisal skills.
5.3 Where should I look for evidence?
It can be extremely time consuming to search the immense volume of published literature available in print and electronically, before locating and then obtaining the relevant evidence (Pravikoff et al 2005). Busy nurses and students need to become aware of the wide range of information resources available in order to make informed decisions about where to look for the best available evidence relevant to their question or topic.
When looking for current evidence, print-based textbooks may not be the best resource in which to locate the evidence because of the time involved in the publication process—generally 1 or 2 years. And although the internet is becoming an increasingly popular tool for quickly locating healthcare information (Gilmour 2007, Korp 2006), it is important to remember that there is no quality control of the internet and that:
… the high-quality and clinically important sources are often hidden in a morass of information that is of questionable, or at least uncertain, quality (McKibbon & Marks 2008:34).
…because the steps of evidence-based nursing practice involve ‘tracking down the best evidence’ with which to answer a clinical question (Sackett et al 2000), understanding the resources available to nurses, as well as their skills in using them, is essential (Pravikoff et al 2005:49).
5.3.1 Databases
A database is a systematic collection of information that is stored, indexed, catalogued, updated regularly and able to be systematically searched. Databases can be categorised as either primary or secondary databases, although some databases may contain both primary and secondary content. However, in general, primary databases contain mostly original reports of research, such as those found in journal articles and conference proceedings, and are written by the researchers themselves (Pearson & Field 2005). CINAHL® (Cumulative Index to Nursing and the Allied Health Literature) is the most well-known example of a primary nursing and allied health database.
CINAHL and other important primary databases such as MEDLINE® (Medical Literature Analysis and Retrieval System Online) and EMBASE contain professional, scholarly, peer-reviewed journals, many of which can only be accessed after payment of subscriptions by university and hospital libraries. As well as providing access to nursing, biomedical and evidence-based databases, hospital and university libraries provide access to key healthcare print and electronic journals through their catalogues and through journal AtoZ title lists. It is important to note that it is common practice for publishers to place an embargo on accessing the latest electronic information (e.g. the last 6, 12 or 18 months). In these instances, the most recent information may only be available in print and not available electronically.
Secondary databases, on the other hand, contain summaries, reviews and appraisals of original primary information, such as systematic reviews, and can be found in the Joanna Briggs Institute (JBI) and the Cochrane Library, which is a collection of secondary databases. The location of systematic reviews is also addressed in Chapter 6.
Table 5.1 focuses on locating research evidence and, while not exhaustive, it includes a comprehensive range of online sources that can be used to search for high-quality evidence. How to appraise and apply this evidence is discussed later in this chapter. Because some of the resources listed in Table 5.1 require a subscription, and often a username and password, in order to access them, it is advisable to check with your university or hospital library as you may be able to access these databases through their institutional licences.
Table 5.1 Locating the evidence
| Secondary databases | What you will find |
|---|---|
| Cochrane Library | High-quality content |
| TRIP | High-quality content |
| Joanna Briggs Institute (JBI) | High-quality content |
| PubMed Clinical Queries | Evidence-based answers to clinical questions |
| BestBETs | Evidence-based answers to clinical questions |
| PEDro | Physiotherapy content |
| OTseeker | Occupational therapy content |
| NICE (UK National Institute for Health and Clinical Excellence) | Evidence-based guidance for nurses and other health professionals |
| SUMSearch | Quality medical content |
| National Guideline Clearinghouse | Evidence-based clinical guidelines |
| Primary databases | What you will find |
| CINAHL | Nursing content (as well as biomedicine and allied health disciplines) • Healthcare books, nursing dissertations, conference proceedings, standards of practice, educational software, audiovisuals and book chapters • Links to full-text journals, legal cases, clinical innovations, critical pathways, drug records, research instruments and clinical trials |
| MEDLINE | Biomedical content |
| EMBASE | Biomedical and pharmaceutical content, with selective nursing content |
| PsycINFO | Psychology content (and related disciplines) • Peer-reviewed citations, summaries and full-text links to scholarly journal articles, book chapters, books and dissertations |
| Science Citation Index (via Web of Knowledge) | Multidisciplinary (sciences) content |
| Current Contents Connect (via Web of Knowledge) | Multidisciplinary content |
5.3.2 Search engines
Popular search engines such as Google and Yahoo are software programs that only retrieve information found on the web and should be used with caution. Search engines vary considerably in terms of their coverage of the web, how frequently they update the websites visited, and the search options offered. In order to retrieve more relevant results, using the advanced search feature is recommended where available. Google Advanced Scholar search allows you to search for phrases, as well as synonyms or related terms, for authors and in named publications to retrieve fewer but more precise results. The instructions available on the advanced search or help pages are also useful.
While search engines can be useful as a quick reference tool, caution is needed in relation to the accuracy and credibility of the information obtained, particularly if healthcare is to be based upon the information found. Search engines will not necessarily retrieve peer-reviewed content (peer-reviewed content is discussed in Section 5.4) and while search engines such as Google Advanced Scholar retrieve better-quality information, there is much scope for further development in this area. Improved search engines designed to selectively access the highest-ranked evidence from multiple databases may be developed, thus allowing clinicians to locate evidence-based content easily. The TRIP (Turning Research Into Practice) Database can be searched in this manner.
5.3.3 Which source should I use?
Table 5.1 provides a list of potential sources of research evidence relevant to nursing practice. It is important to note that while these resources are well established, other resources may be developed in the future or there may be resources already of considerable relevance to particular fields of nursing that are not listed. Some workplaces and universities may also have licensed access to specific databases not listed here. Furthermore, while the resources listed are unlikely to disappear, their URLs may change over time. For these reasons, workplaces with internet access may find it useful to set up a small index of the most relevant databases. An excellent example of such an index for evidence-based health practice is provided by the Flinders University Library in South Australia (see www.lib.flinders.edu.au/resources/sub/medicine/ebm.html). See Chapter 1 for other comparable resources.
Constructing an index or portal of evidence-based resources is a useful first step in dealing with both information overload and content of questionable credibility. The next strategy is to consider which specific resources from Table 5.1 should be searched first. This will depend upon the reasons for your search and the type of question you are asking.
For example, if primary evidence is required, large electronic databases such as CINAHL, MEDLINE or EMBASE will provide access to the original study or the latest journal article. Secondary resources such as the Cochrane Library and the JBI provide critical summaries or systematic reviews of the best available research evidence (also discussed in Ch 6). A PhD student undertaking a research project would need to undertake a comprehensive search for evidence across a variety of resources, while the information required to answer a clinical question may be relatively quick and simple to locate using just one resource.
Having said this, it is worthwhile remembering that no one database is likely to identify all sources of potentially relevant data. Each database has unique characteristics, not just in terms of layout or display, but more importantly in terms of the content and the tools used to locate the most relevant information. To illustrate this point, let us consider and compare two useful, comprehensive primary databases for nursing: CINAHL and MEDLINE.
It is clear that searching multiple sources is always recommended due to variability in yield (results) for the search terminology selected and the unique collections in each database (Morrissey & DeBourgh 2001).
