Introduction to Nursing Research: Review of Literature

A review of literature is a comprehensive description as well as an evaluation of the evidence related to a given topic. Review of literature sets the stage for the reminder of the article. An effective relevant literature includes those studies which have been completely executed, clearly reported and closely related to the research problem. Well-written reviews of literature include evaluative statements regarding the studies described. Comment about sample size, instruments used, research design, and other components of the research process can be helpful to the reader in better understanding the value of the results of the investigations.In conducting an in-depth search of the literature, the investigator needs to identify all relevant publications in the area of interest.

The investigator starts with the most recent publications in order to find the most relevant information. When searching the literature both primary and secondary sources may need to be considered A primary source refers to the publication in its original form. A secondary source refers when the author writes about another authors work. Primary sources are generally preferred because a distortion of ideas can occur in a secondary source (Polit & Hungler, 1999).

The investigator critically evaluates the information gathered by examining each component of the publication. Analysis of a clinical opinion article requires the reader to evaluate the logic to validate the author’s conclusion. When examining a research report, the reader must examine each component of the research process and make judgments about the appropriateness of the methods used in relation to the conclusion drawn (Brockopp & Hastings-Tolsma, 2003).

There are two methods of searching literature, performing computer search in databases, and examining books and periodicals manually. A combination of two methods can be comprehensive. For manual search for information related to a given topic the investigator can use library facilities with the help of library mechanisms like card catalogs or computer catalogs.Computerized databases are increasingly popular and necessary as the volume of published material continues to grow.

Computer searches are more advantageous than hand searches of indexes because they take less time and allow concepts to be linked (Sinclair, 1987). Searching by computer can be accomplished using a library-based computer system or a personal computer and online resources in the home or workplace. The computer also allows the researcher to choose only the references of interest form those presented and to obtain a printed list of articles chosen fro review.

The internet possesses an enormous number of medical and nursing databases, which are very useful for nursing professionals. It is quiet impossible to calculate the quantity of medical information on the Internet. So many new resources are created each day that nobody could possibly keep abreast of them and present an exhaustive analysis of all existing medical resources. MEDLINE is a comprehensive database for health literature which is managed by National Library of Medicine, USA. International nursing index and IndexMedicus are included in MEDLINE. Cochrane Review (www.cochranereview.org) is another database which gives extensive search options. Cumulative Index to Nursing and Allied Health Literature (CINAHL) is a database of exclusive nursing articles. Internet search engine Google has developed Google Scholar (http://scholar.google.com ), which helps to confine search options to academic papers only. Open access journals (http://doaj.org) are another source of searching literature. These journals are access free and can be used without restriction provided the policies are accepted. Many standard journals provide their archives for free online access search after a period of time to developing countries. Elsevier publications’ internet database for nursing journals is accessible at http://sciencediretct.com/. The Nursing Center (http://nursingcenter.com ) is the online access site for Lippincott Williams & Wilkins’ nursing journals. These journals are to be subscribed and most of them are indexed in MEDLINE and CINAHL. Many of the journals are published by the organization themselves. The Indian Medlars Centre of National Informatics Centre, New Delhi, has designed two databases, IndMED, a bibliographic database of peer reviewed Indian biomedical journals and medIND, full-text of selected IndMED journals. These are accessible free of cost from the Center’s site <http://indmed.nic.in/> (Ameen, 2004).

Bradford-Hill criteria are nine specific criteria that are used to evaluate studies for the existence of a cause-and –effect relationship. The nine criteria are the strength of the association, confounding variables and bias, temporality, biologic gradient, specificity, consistency, biologic plausibility, studies appropriately done(having clear comparison group, blinding description of the methods used, analysis consistence with study design), and freedom from bias and confounding variables. Consistent use of the criteria helps in the determination that the increased relative risk is not likely the result of bias or other factors (Bradford-Hill, 1971).

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