SYSTEMATIC REVIEWS , Step by Step The Systematic Review : An Overview Synthesizing research evidence to inform nursing practice

Research in the health sciences has provided all health care professions, including nursing, with much new knowledge to inform the prevention of illness and the care of people with ill health or trauma. As the body of research has grown, so too has the need for rigorous syntheses of the best available evidence. Literature reviews have long been a means of summarizing and presenting overviews of knowledge, current and historical, derived from a body of literature. They often make use of the published literature; generally, published papers cited in a literature review have been subjected to the blind peer-review process (a hallmark of most scientific periodicals). The literature included in a literature review may encompass research reports that present data, as well as conceptual or theoretical literature that focuses on a concept. An author may conduct a literature review for a variety of reasons, including to • present general knowledge about a topic. • show the history of the development of knowledge about a topic. • identify where evidence may be lacking, contradictory, or inconclusive. • establish whether there is consensus or debate on a topic. • identify characteristics or relationships between key concepts from existing studies relevant to the topic. • justify why a problem is worthy of further study. All of these purposes have been well served by a “traditional” or “narrative” review of the literature. Traditional literature reviews, though useful, have major drawbacks in informing decision making in nursing practice. Predominantly subjective, they rely heavily on the author’s knowledge and experience and provide a limited, rather than exhaustive, presentation of a topic. Such reviews are often based on references chosen selectively from the evidence available, resulting in a review inherently at risk for bias or systematic error. Traditional literature reviews are useful for describing an issue and its underlying concepts and theories, but if conducted according to no stated methodology, they are difficult to reproduce—leaving the findings and conclusions resting heavily on the insight of the authors. 2 In many cases, the author of the traditional review discusses only major ideas or results from the studies cited rather than analyzing the findings of any single study. With the advent of evidence-based health care some 25 years ago, nurses and other clinicians have been expected to refer to and rely on research evidence to inform their decision making. The need for evidence to support clinical practice is constantly on the rise because of advances that continually expand the technologies, drugs, and other treatments available to patients. Nurses must often decide which strategies should be implemented, yet comparisons between available options may be difficult to find because of limited information and time, particularly among clinical staff. Furthermore, interpreting research findings as presented in scientific publications is no easy task. Without clear recommendations for practice, it can be difficult to use evidence appropriately; it requires some knowledge of statistics and in some cases extensive knowledge or experience in how to apply the evidence to the clinical setting. Also, many health care devices and drugs come with difficult-to-understand claims of effectiveness. As a result of research, the knowledge on which nursing care is based has changed at a rapid pace. By Edoardo Aromataris, PhD, and Alan Pearson, PhD, RN