Literature review

Osama A Samarkandi, PhD, RN

BSc, GMD, BSN, MSN, NIAC

EMS 423; EMS Research and Evidence Based Practice

BASIC ISSUES RELATING TO LITERATURE REVIEWS

Purposes of Research Literature Reviews

• Literature reviews can inspire new research ideas.

• helps to lay the foundation for studies.

• suggest appropriate methods, and point to a conceptual or theoretical framework

• A literature review also helps researchers to interpret their findings.

Types of Information to Seek for a Research Review

• primary source research reports: which are descriptions of studies written by the researchers who conducted them.

• Secondary source research documents: are descriptions of studies prepared by someone other than the original researcher.

• opinion articles.• case reports.• clinical anecdotes.

Major Steps and Strategies in Doing a Literature Review

• start with a question

• Formulate and implement a plan for gathering information.

• analyze and interpret the information.

• Then the “findings” are usually summarized in a written product.

characterize a high-quality review:

• comprehensive

• systematic.

• reproducible.

• balance and the absence of bias.

LOCATING RELEVANT LITERATURE

FOR A RESEARCH REVIEW

Formulating a Search Strategy

1- searching for references through the use of bibliographic databases.

2- ancestry approach is to use the citations from relevant studies to track down earlier research on which the studies are based.

3- the descendancy approach, is to find a pivotal early study and to search forward in citation indexes to find more recent studies.

Searching Bibliographic Databases

• Electronic Search.

• The CINAHL Database.

• The MEDLINE Database

Electronic Search.

• An early task in doing an electronic search is to identify keywords to launch the search.

• For quantitative studies, the keywords you begin with are usually the primary independent or dependent variables.

• For qualitative studies, they keywords would be the central phenomenon of interest and the population.

The CINAHL Database.

• It covers references to virtually all English-language nursing and allied health journals, as well as to books, book chapters, dissertations, and selected conference proceedings.

• CINAHL provides bibliographic information for locating references (i.e., the author, title, journal, year of publication, volume, and page numbers), as well as abstracts of most citations.

The source indicates the following:

* Name of the journal (Pain Management Nursing)

* Year and month of publication (2007 Dec)

* Volume (8)

* Issue (4)

* Page numbers (156–65)

* Number of cited references (33)

The MEDLINE Database

• PubMed website.

(http://www.ncbi.nlm.nih.gov/PubMed)

Screening and Gathering References

• totally practical—is the reference readily accessible? For example, full dissertations may not be easy to retrieve.

• the relevance of the reference, which you can usually surmise by reading the abstract.

• the study’s methodologic quality—that is, the quality of evidence the study yields.

Documentation in Literature Retrieval

• It is wise to maintain a notebook (or computer database program) to record your search strategies and results.

• You should make note of information such as databases searched; limits put on your search; specific keywords, subject headings, and authors used to direct the search; websites visited.

• Part of your strategy can be documented by printing your search history from the electronic databases.

Abstracting and Recording Information

EVALUATING AND ANALYZING THE EVIDENCE

Evaluating Studies for a Review• evaluate the quality of each study so that you could draw

conclusions about the overall body of evidence and about gaps in the evidence base.

• Critiques for a literature review tend to focus on methodologic aspects.

• answering a very broad question: To what extent do the findings, taken together, reflect the truth

• to what extent do biases and flaws undermine the believability of the evidence?

Characteristics of good LR

• use powerful designs.

• good sampling plans.

• strong data collection instruments and procedures.

• appropriate analyses.

Analyzing and Synthesizing Information

types of themes can be identified in a literature review analysis.

Substantive themes: • What is the pattern of evidence? • How much evidence is there? • How persuasive is the evidence? • What gaps are there in the body of evidence?

Methodologic themes: • What designs and methods have been used to address

the question?

• What methodologic strategies have not been used?

• What are the predominant methodologic deficiencies and strengths?

Generalizability/transferability themes: • To what types of people or settings do the findings

apply? • Do the findings vary for different types of people (e.g.,

men versus women) or setting (e.g., urban versus rural)?

Historical themes: • Is the evidence getting better? • When was most of the research conducted?

“Researcher” themes: • Who has been doing the research, in terms of discipline,

specialty area, nationality, prominence, and so on?

PREPARING A WRITTEN LITERATURE REVIEW

Organizing the Review

• summarize information in a table. The table could include columns with headings such as Author, Sample Characteristics, Design, Data Collection Approach, and Key Findings.

• have a plan before starting to write so that the review has a meaningful and understandable flow.

Writing a Literature Review

• Content of the Written Literature Review.

• Style of a Research Review.

• Length of a Research Review.

Content of the Written Literature Review.

• A written research review should provide readers with an objective, well-organized synthesis of the current state of evidence on a topic.

• The central tasks are to summarize and critically evaluate the overall evidence so as to reveal the current state of knowledge on a topic with regard to themes deemed to be important.

• The literature should be summarized in your own words.

• The review should demonstrate that consideration has been given to the cumulative worth of the body of research.

Style of a Research Review.

• When describing study findings, you should generally use phrases indicating tentativeness of the results:

* Several studies have found . . .

* Findings thus far suggest . . .

* The results are consistent with the conclusion that . . .

* Results from a landmark study imply that . . .

* There appears to be fairly strong evidence that . . .

Length of a Research Review.

• There are no formulas for how long a review should be.

• The length depends on several factors, including the complexity of the question, the extent of prior research, and the purpose for which the review is

being prepared.

GUIDELINES FOR CRITIQUING LITERATURE REVIEWS

1. Does the review seem thorough—does it include all or most of the major studies on the topic? Does it include recent research?

2. Does the review depends on appropriate materials?

3. Is the review merely a summary of existing work?

4. Is the review well organized? Is the development of ideas clear?

5. Does the review use appropriate language, suggesting the tentativeness of prior findings?

6. If the review is part of a research report for a new study, does the review support the need for the study?

Questions ?