Review of Relevant Literature

Review of Relevant Literature


You have been asked to present a lecture about home health care for undergraduate nursing students. Maybe you are concerned about the families of the patients in your critical care unit and want to devise a program to address their unique needs. Maybe you are a graduate nursing student and your teacher said your paper needed to include a review of the literature. Maybe you are in a Magnet hospital and the nurses on your unit are developing a proposal for a study. In each situation, you need to understand how to review the literature and to present the information you find in a logical, synthesized manner. By building on previous knowledge, nurse researchers can add to the evidence upon which we base our practice.

The rate of new knowledge being generated each year continues to grow. Early studies in the 1960s indicated that knowledge doubled every 13 to 15 years (Larsen & von Ins, 2010). The vast amount of information available within seconds implies that knowledge is doubling much more rapidly in the digital age. Bachrach (2001) noted that each new discipline launches new journals to develop its disciplinary knowledge. Computerized bibliographical databases have made the process of searching for relevant empirical or theoretical literature easier in some ways, but you are faced with the dilemma of selecting the most relevant sources from a much larger number of articles. The task of reading, critically appraising, analyzing, and synthesizing has expanded and can consume any time gained by more efficient searching. This chapter provides basic skills and knowledge to identify evidence for changing nursing practice, developing a research proposal, preparing a lecture, or writing a manuscript.

What Is “The Literature”?

“The literature” consists of all written sources relevant to the topic you have selected. The literature consists of newspapers, monographs, encyclopedias, conference papers, scientific journals, textbooks, other books, theses, dissertations, and clinical journals. Websites and reports developed by government agencies and professional organizations are also included. For example, to support the significance of diabetes mellitus as a topic for a research study, you could find statistics about the prevalence and cost of the disease from the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO). Not every source that you find, however, will be valid and legitimate for scholarly use. The website of a company that sells insulin may not be an appropriate source for diabetes statistics. Online encyclopedias to which anyone can contribute, such as Wikipedia, are not considered scholarly sources. These websites might point you toward professional sources but should not be cited in a professional or academic paper. You should use primary, peer-reviewed, professional literature. New knowledge develops when researchers and scholars produce manuscripts for journals and books that are reviewed by peers to determine whether the manuscripts should be published.

What Is a Literature Review?

The literature review is an organized written presentation of what you find when you review the literature. The literature review is “central to scholarly work and disciplined inquiry” (Holbrook, Bourke, Fairbairn, & Lovat, 2007, p. 337); it summarizes what has been published on a topic by scholars and presents relevant research findings. Developing the ability to write coherently about what you have found in the literature requires time and guidance. The review should be organized into sections that present themes, identify trends, or examine variables. The purpose is not to list all the material published but, rather, to synthesize and evaluate it on the basis of the phenomenon of interest.

The focus of the review depends on the reason you are reviewing the literature. This overview describes common purposes for conducting literature reviews; however, the goal of this chapter is to provide specific guidance and practical suggestions related to reviewing research relevant to a proposed study. The three major stages of literature reviews are discussed: (1) searching the literature, (2) processing the literature, and (3) writing the literature review.

Purposes of Reviewing the Literature

Writing a Course Paper

For most course papers, your instructor will expect you to review published sources on the topic of your paper. Reviews of the literature for a course assignment will vary depending on the level of educational program, the purpose of the assignment, and the expectations of the instructor. The literature review for a graduate course is expected to have greater depth, scope, and breadth than a review for an undergraduate course (Hart, 2009). A paper in a nurse practitioner course might require that you review pharmacology and pathology reference books in addition to journal articles. In a nursing education course, you may review neurological development, cognitive science, and general education publications to write a paper on a teaching strategy. For a doctor of nursing practice course on clinical information systems, your review might need to extend into computer science and hospital management literature. For a theory course in a doctor of philosophy in nursing program, your review may need to include all the publications of a specific theorist or all the studies based on the theory. For each of these papers, your professor may specify the publication years and the type of literature to be included. Also, you must note the acceptable length of the written review of the literature to be submitted. Reviews of the literature for course assignments tend to focus on what is known, the strength of the evidence, the implications of the knowledge, and what is not known for the purpose of developing new studies.

Developing a Qualitative Research Proposal

In qualitative research, the purpose and timing of the literature review depend on the type of study to be conducted (see Chapter 12). Some phenomenologists believe that the literature should not be reviewed until after the data have been collected and analyzed, so that the literature does not interfere with the researcher’s ability to suspend what is known and to approach the topic with openness (Munhall, 2012). In the development of a grounded theory study, a minimal review of relevant studies provides the beginning point of the inquiry, but this review is only a means of making the researcher aware of what studies have been conducted. This information, however, is not used to direct the collection of data or interpretation of the findings in a grounded theory study. During the data analysis stage, a core variable is identified and the researcher theoretically samples the literature for extant theories that may assist in explaining and extending the emerging theory (Munhall, 2012). In historical research, the initial review of the literature helps the researcher define the study questions and make decisions about relevant sources. The data collection is actually an intense review of published and unpublished documents that the researcher has found.

The purposes of reviewing the literature for ethnographic studies and for exploratory descriptive qualitative research are more similar to that for quantitative research. The researcher develops a general understanding of the concepts to be examined in relation to the selected culture or topic. The literature review also provides a background for conducting the study and interpreting the findings. Chapter 12 describes in more detail the role of the literature review in qualitative research.

Developing a Quantitative Study

The review of literature in quantitative research directs the development and implementation of a study. The focus of the major literature review at the beginning of the research process is to identify a gap in what is known. The study is designed to add knowledge in the area of the identified gap. For example, an intervention to prevent hospital-acquired infections related to intravenous infusions has been shown to reduce the incidence of these infections among postoperative patients who have no history of diabetes mellitus. After a thorough review of the literature, the researcher identifies a specific gap in knowledge. What is not known is whether this intervention will be equally effective for postoperative patients who have diabetes. After the data have been analyzed and the findings described, the researcher will return to the literature in the generalization phase of the research report to integrate knowledge from the literature with new knowledge obtained from the study. The purposes of the literature review are similar for the different types of quantitative studies (descriptive, correlational, quasi-experimental, and experimental).

Table 6-1 describes the role of the literature throughout the development and implementation of the study. The types of sources needed and how you will search the literature will vary throughout the study. The introduction section uses relevant sources to summarize the background and significance of the research problem. The review of the literature section includes both theoretical and empirical sources that document the current knowledge of the problem. The researcher develops the framework section from the theoretical literature and sometimes from empirical literature. If little theoretical literature is found, the researcher may need to develop a tentative theory to guide the study from the findings of previous research studies (see Chapter 7 for more information). The methods section describes the design, sample, measurement methods, treatment, and data collection process of the planned study and is based on previous research. Thus, previous studies may be cited in the methods section. In the results section, sources are included to document the different types of statistical analyses conducted and the computer software to conduct these analyses. The discussion section of the research report begins with what the results mean in light of the results of previous studies. Conclusions are drawn that are a synthesis of the cited findings from previous research and those from the present study.


The Role of the Literature Review in Developing a Quantitative Research Proposal

Phase of the Research Process How Literature Is Used and Its Role
Research topic Broad searches using keywords to understand the extent of what is known and what is not known; what concepts are related to the topic
Statement of the research purpose From your synthesis of the literature, the specific gap in knowledge that this study will address
Background and significance Searches of books and articles to provide an overview of the topic
Identification of the size, cost, and consequences of the research problem
Research framework Find and read relevant theories
Facilitate development of the framework
Develop conceptual definitions of concepts
Purpose of the study On the basis of your knowledge of the literature, state the purpose of the study
Research objectives, questions, or hypotheses On the basis of the knowledge gained from and examples found in the literature, write the objectives or questions of the study
If sufficient literature allows a prediction, state the hypotheses of the study
Review of the literature Find sources as evidence for logical argument for why this study and methodology are needed
Summarize current empirical knowledge that is related to the topic
Methodology Compare research designs of reviewed studies to select the most appropriate design for the proposed study
Identify possible instruments or measures of variables
Provide operational definitions of concepts
Describe performance of measures in previous studies
Develop sampling strategies based on what you have learned from the studies in the literature
Findings Refer to statistical textbooks to explain the results of the data analysis
Discussion Compare your findings with those of studies you have previously reviewed
Return to the literature to find new references to interpret unexpected findings
Identify limitations of the study
Refer to theory sources to relate the findings to the research framework
Conclusions On basis of your knowledge of the literature and your study’s findings, draw conclusions
Discuss implications for nursing clinical practice, administration, and education
Propose future studies

Practical Considerations

What Types of Literature Can I Expect to Find?

Two broad types of literature are cited in the review of literature for research: theoretical and empirical. Theoretical literature consists of concept analyses, models, theories, and conceptual frameworks that support a selected research problem and purpose. Empirical literature comprises knowledge derived from research. The empirical literature reviewed depends on the study problem and the type of research conducted. Research problems that have been frequently studied or are currently being investigated have more extensive empirical literature than new or unique problems. If searching the empirical literature, you need to identify seminal and landmark studies. Seminal studies are the first studies that prompted the initiation of the field of research. Nurse researchers studying hearing loss in infants would need to review the seminal work of Fred H. Bess, an early researcher on this topic who advocated for effective screening tools (Gravel, 2009). Critical care nurses comparing correction formulas for QT intervals on electrocardiograms would want to refer to Bazet’s correction formula. The development of the formula can be traced to his seminal paper, published in 1920, on time-relations in electrocardiograms (Roguin, 2011). Landmark studies are the studies that led to an important development or a turning point in the field of research. For example, researchers conducting studies related to glycemic control must be knowledgeable of the implications of the Diabetes Control and Complications Trial, a longitudinal study whose findings changed diabetic care beginning in the mid-1990s (Everett, Bowes, & Kerr, 2010).

Literature is disseminated in several different formats. Serials are published over time or may be in multiple volumes but do not necessarily have predictable publication dates. Periodicals are subsets of serials with predictable publication dates, such as journals, which are published over time and are numbered sequentially for the years published. This sequential numbering is seen in the year, volume, issue, and page numbering of a journal. Monographs, such as books, hard-copy conference proceedings, and pamphlets, are usually written once and may be updated with a new edition as needed. Conference proceedings can help you identify major researchers in your research area who have presented findings that may not yet be published. Periodicals and monographs are available in a variety of media, such as print, online, CD-ROM, and downloadable formats. Textbooks are monographs written to be used in formal education programs.

Entire volumes of books available in a digital or electronic format are called eBooks (Tensen, 2010). You may be familiar with digital books in the mass publication literature that are available to download to read on a special reading device, such as a Kindle or Nook. eBooks are also available for scholarly volumes and articles that can be downloaded to a reading device, cell phone, laptop, or other computer. Books that in the past would have been difficult to obtain through interlibrary loan are now available 24 hours a day, 7 days a week as eBooks.

To develop the significance and background section of a proposal, you may also need to search for government reports for the United States (U.S.) and other countries, if appropriate for your study. A researcher developing a proposal on task shifting in HIV care settings in low-resource countries would search the Ministry of Health websites for those countries to find official guidelines for this type of practice. Researchers developing a proposal in Wisconsin on the smoking cessation in adolescents would consult the Healthy People 2020 website for the national goals related to this topic ( They may also explore health-related agencies in Wisconsin to determine information specific to their state.

Position papers are disseminated by professional organizations and government agencies to promote a particular viewpoint on a debatable issue. Position papers, along with descriptions of clinical situations, may be included in the discussion of the background and significance of the research problem. A researcher developing a proposal on race-related differences in HIV treatment outcomes would want to review the Association of Nurses in AIDS Care position paper, “Health Disparities,” which the organization’s board approved in 2009.

Master’s theses and doctoral dissertations are valuable literature as well but may not be published. A thesis is a research project completed as part of the requirements for a master’s degree. A dissertation is an extensive, usually original research project that is completed as the final requirement for a doctoral degree. Theses and dissertations can be found by searching special databases that are available for these publications, such as ProQuest Dissertations and Theses (

The published literature contains primary and secondary sources. A primary source is written by the person who originated, or is responsible for generating, the ideas published. A research publication published by the person or people who conducted the research is a primary source. A theoretical book or paper written by the theorist who developed the theory or conceptual content is a primary source. A secondary source summarizes or quotes content from primary sources. Thus, authors of secondary sources paraphrase the works of researchers and theorists. The problem with a secondary source is that its author has interpreted the works of someone else, and this interpretation is influenced by that author’s perception and bias. Authors have sometimes spread errors and misinterpretations by using secondary sources rather than primary sources. You should use mostly primary sources to write literature reviews. Secondary sources are used only if primary sources cannot be located or if a secondary source contains creative ideas or a unique organization of information not found in a primary source. Citation is the act of quoting or paraphrasing a source, using it as an example, or presenting it as support for a position taken.

How Long Will the Review of the Literature Take?

The time required to review the literature is influenced by the problem studied, sources available, and goals of the reviewer. The literature review for a topic that is focused and somewhat narrow may require less time than one for a topic that is broad. The difficulty you experience identifying and locating sources and the number of sources to be located also influence the time involved, as does the intensity of effort. Only through experience does one become knowledgeable about the time needed for a literature review.

The novice reviewer requires more time to find the relevant literature than an experienced searcher, and the novice frequently underestimates the time needed for the review. An experienced librarian who works closely with nursing graduate students on a variety of course assignments recommends that the reviewer estimate the time required on the basis of the number of sources required and the reviewer’s familiarity with the library’s databases. The reviewer knows he or she needs at least 30 sources and that finding these sources may require 10 hours of searching. The reviewer estimates that it will take another 20 hours to read and synthesize the sources. The reviewer estimates that the review will require 30 hours. The reviewer should then multiply that number by four, making the estimated time required for the review 120 hours. This longer estimate is often more realistic. As searching skills are refined, the need to use this expanded estimate reduces. Often, the literature review is limited by the time that the reviewer can commit to the assignment. The conclusion related to the time issue is to start as early as possible and stay focused on the purpose of the review.

How Many Sources Do I Need to Review?

Students repeatedly ask, “How many articles should I have? How far back in years should I look to find relevant information?” The answer to both those questions is an emphatic “It depends.” Course faculty for masters courses commonly require that you obtain full-text articles of all studies relevant to the variables in the proposed study that were published in the previous 10 years. The instructors often indicate, however, that the length of time may vary depending on the topic and the presence of classic studies. Doctoral students are expected to conduct a more extensive review for course papers. If you are writing a research proposal for a thesis or dissertation, the literature required will be extensive. You need to locate the key papers in the field of interest. After doing some initial searches, discuss what you find with your instructor, thesis chair, or dissertation chair, who will be able to help you determine a reasonable publication period for you to use in your review.

Am I Expected to Read Every Word of the Available Sources?

The answer is “No.” If researchers attempted to read every word of every source that is somewhat related to a selected problem, they would be well read but would probably never complete their searches or move on to developing study proposals. Some individuals, even after a thorough literature review, continue to believe that they do not know enough about their area of interest, so they persist in their review; however, this activity ultimately becomes an excuse for not progressing with their work. The opposite of this situation is the individual who wants to move rapidly through the review of literature to reach the conclusion or get to the part of the work that is more enjoyable or important.

With the availability of full-text online articles, the researcher can easily get “lost in the literature” and forget the focus of the review. Becoming a skilled reviewer of the literature involves finding a balance and learning to identify the most pertinent and relevant sources. On the other hand, you cannot critically appraise and synthesize what you have not read. Avoid being distracted by nonrelevant information provided by the author. Learn to read with a purpose and involve multiple senses in your reading. Try reading aloud a section that you have difficulty understanding. Are you having difficulty following an author’s presentation? Try writing an outline. Draw a diagram of key points. Audio record your thoughts on the content of an article. Listen to soothing music if you are tense or anxious. Listen to music with an upbeat tempo if you are tired and having trouble staying awake. Try reading in a quiet place outside or standing up with the copy of the article or your laptop on a counter or high table. Involving multiple senses while reading may help you stay awake and focused.

Stages of a Literature Review

The stages of a literature review reflect a systems model. Systems have input, throughput, and output. The input consists of the sources that you find through searching the literature. The throughput is the processes you use to read, critically appraise, analyze, and synthesize the literature you find. The written literature review is the output of these processes (see Figure 6-1). The quality of the input and throughput will determine the quality of the output. As a result, each stage of the literature review is critical to producing a high-quality literature review. Although these stages are presented here as sequential, you may go back to a previous stage. For example, during the analysis and synthesis of your sources, you identify that the studies you are citing were conducted only in Europe. You might go back and search the literature again using the United States or another search term to ascertain that no studies have been done in that country. As you are writing your literature review, you may identify a problem with the logic of your presentation. To resolve it, you may return to the processing stage to clarify the presentation.

Searching the Literature

Before writing a literature review, you must first perform literature searches to identify sources relevant to your topic of interest. The literature review will help you narrow your topic and develop a feasible study (Hart, 2009). Whether you are a student, practicing nurse, or nurse researcher, your goal is to develop a search strategy designed to retrieve as much of the relevant literature as possible given the time and financial constraints of your project.

Libraries have become gateways to information or information resource centers, rather than storehouses of knowledge (Hart, 2009). High-quality libraries provide access to a large number of electronic databases that supply a broad scope of the literature available internationally, enabling library users not only to identify relevant sources quickly but also to read full-text versions of most of these sources immediately. When your library does not have the hard copy of a book or electronic access to a specific journal, the librarian can usually provide the book or an electronic copy of the article through interlibrary loan. All libraries, public, private, college, and university, have interlibrary loan capabilities. You may especially need to use interlibrary loan when sources relevant to your topic were published prior to the advent of electronic databases.

Consider consulting with an information professional, such as a subject specialist librarian, to develop a literature search approach (Booth, Colomb, & Williams, 2008; Tensen, 2010). Often these consultations can be performed via email or a web-based meeting, so that communication occurs at the convenience of both the researcher and the information professional. Many university libraries provide this consultation service whether or not the library user is affiliated with the university.

Develop a Search Plan

Before you begin searching the literature, you must consider exactly what information you are seeking. Expending time and effort in the early stage of a review to develop a search strategy is likely to save time and effort later (Hart, 2009). A written plan helps you to avoid duplication of effort, to return to a previously searched area with a different set of search terms or a different range of publication years. Your initial search should be based on the widest possible interpretation of your topic. This strategy enables you to envision the extent of the relevant literature. As you see the results of the initial searches and begin reading the material, you will refine your topic, and then you can narrow the focus of your searches.

As you search, add your selected search terms to your written search plan. As you search, add other terms that you discover from the references you locate. For each search, record (1) the name of the database, (2) the date, (3) search terms and searching strategy, (4) the number and types of articles found, and (5) an estimate of the proportion of the citations you retrieved that were relevant articles. Table 6-2 is an example of search history that you can use to record what and how you have searched the literature. Save the results of each search on your computer or external device. Some databases allow you to create an account and save your search history online (i.e., the record of what and how you searched).

Select Databases to Search

A database is computer data that have been collected and arranged to be searchable and automatically retrievable (Tensen, 2010). A bibliographical database is an “an electronic version of a bibliographic index” (p. 57) or compilation of citations. The database may consist of citations relevant to a specific discipline or may be a broad collection of citations from a variety of disciplines. Databases of periodical citations include the authors, title, journal, keywords, and usually an abstract of the article. Library databases contain titles and authors of hard copy books and documents, government reports, and reference books. Library databases also include a searchable list of the journals to which the library has a paper or electronic subscription. For example, your library may have received paper copies of a monthly journal in the mail until 2006. The hard copies of the issues were bound to create annual volumes of the journal. Since 2006, the library has subscribed to the electronic journal or a journal database that provides access to specific issues.

Bibliographical databases provided by the same vendor, such as those databases affiliated with EBSCO Publishing, allow you to search multiple databases simultaneously to save time. Usually the search engine will automatically delete duplicates of the same study. You can also change the order in which the results of the search are shown. For example, with the EBSCO Publishing databases, you can sort the citations by relevance, date descending (most current first), or date ascending (oldest to more recent).

Older sources of reference indexes are useful for sources published prior to the electronic databases. Card catalogs, abstract reviews, and indexes were the only ways to search for nursing references until 1955, when the Cumulative Index to Nursing and Allied Health Literature (CINAHL) began being published. Because the printed editions had red covers, you still may hear more experienced scholars fondly refer to “the Red Books.” The print version of CINAHL is still available in libraries, and you may find it useful when searching for citations published before 1982 or when bibliographic databases are not available (Tensen, 2010). In medicine, the Index Medicus (IM) was first published in 1879 and is the oldest health-related index. The Index Medicus includes some citations of nursing publications, with the number of nursing journals cited growing. CINAHL contains, however, a more extensive listing of nursing publications and uses more nursing terminology as subject headings. With the greater focus on interdisciplinary research, nurse researchers must also be consumers of the literature in the National Library of Medicine (MEDLINE), other government agencies, and professional organizations. Table 6-3 provides descriptions of commonly used bibliographical databases.


Bibliographical Databases

Name of Database Description of the Database by the Publisher*
Cumulative Index of Nursing and Allied Health Literature (CINAHL) “Comprehensive source of full text for nursing & allied health journals, providing full text for more than 770 journals”
MEDLINE “Information on medicine, nursing, dentistry, veterinary medicine, the health care system, pre-clinical sciences, and much more”
Created and provided by the National Library of Medicine
Uses Medical Subject Headings (MeSH terms) for indexing and searching of “citations from over 4,800 current biomedical journals”
PubMed Free access to Medline that provides links to full-text articles when available
PsychARTICLES 15,000 “full-text, peer-reviewed scholarly and scientific articles in psychology”
Limited to journals published by the American Psychological Association (APA) and affiliated organizations
PsychINFO “Scholarly journal articles, book chapters, books, and dissertations, is the largest resource devoted to peer-reviewed literature in behavioral science and mental health”
Supported by APA
Covers over 3 million records
Academic Search Complete “Comprehensive scholarly, multi-disciplinary full-text database, with more than 8,500 full-text periodicals, including more than 7,300 peer-reviewed journals”
Health Source Nursing/ Academic Edition “Provides nearly 550 scholarly full text journals focusing on many medical disciplines”
Also includes 1,300 patient education sheets for generic drugs
Psychological and Behavioral Sciences Collection “Comprehensive database covering information concerning topics in emotional and behavioral characteristics, psychiatry & psychology, mental processes, anthropology, and observational & experimental methods”
400 journals indexed

*Direct quotations from EBSCO Publishing descriptions of the databases, available at

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Feb 17, 2017 | Posted by in NURSING | Comments Off on Review of Relevant Literature

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