obtains relevant literature (Cooper, 1998). This begins the data collection phase
of the systematic review. Through an exhaustive process, both published and
unpublished literature is sought for the review. Because most published studies
have significant findings, including unpublished literature helps to decrease bias.
Computerized databases are searched, including Cumulative Index to Nursing
and Allied Health Literature (CINAHL), MEDLINE, Psyc INFO, Health-STAR,
the Cochrane Library, Google Scholar, and Dissertation Abstracts Online.
Keywords are used to query the databases. Additional computerized databases
may also be used, depending on the selected topic. For example, if the author
were conducting a systematic review on a topic related to geriatric nursing, the
Age Line Database would be included.
The author of the review should consult with expert health science information
specialists during the search. These specialists can locate more studies than less
experienced researchers can (Conn, Valentine, Cooper, & Rantz, 2003; Cook,
Guyatt, & Ryan, 1993). The author must also search for additional published
literature through the ancestry approach. This strategy is completed when the
reference lists of articles are carefully reviewed for any additional articles that
are pertinent to the review. Hand searches of journals in which other eligible
articles have been found should also be completed. Locating all pertinent re-
search reports is critical to enhancing external validity of the systematic review.
External validity is the ability to generalize the findings from a study, in this
case a systematic review, to another situation (e.g., clinical practice).
The next phase of the systematic review involves evaluation of the literature
(Cooper, 1998). Each piece of literature can be conceptualized as a subject, much
like a subject in primary research. Each piece of literature is evaluated for its
contribution to the problem and posed questions. A typical approach for data
evaluation involves a data collection tool similar to the grid within this text’s
digital resources that you are developing in the Apply What You Have Learned
exercise. A table such as this is often created, where each evaluation criterion is
listed and data that are extracted from each report are placed into the format.
Depending on the question to be answered by the systematic review, data evalu-
ation may include gathering author, year, study purpose, research question/
hypothesis, variables studied, sample size, sample age, setting, research design,
research instruments used to measure each variable, instrument psychometrics,
procedures used for data collection, and study results.
The next phase of the systematic review process is data (Cooper, 1998). This
stage is defined as “reducing the separate data collection points collected by
the inquirer into a unified statement about the research problem” (Cooper,
1998, p. 104). The goal of the systematic review determines the data analysis
approach used. On one hand, reviews of concepts, definitions, and methods
are best summarized qualitatively. On the other hand, if the body of reports
12.1 The Pyramid of the 5 Ss 315