literature section of the study. This section usually ends
by identifying a gap in current knowledge about the phe-
nomenon of interest. The purpose of the proposed study
should be to fill some portion of that gap in knowledge with
the research questions or hypotheses determining what
specific new knowledge will be generated. The research
design should flow from the stated purpose and provide a plan that can answer
the research questions and test the stated hypotheses.
Quantitative designs used to examine relationships among variables are
categorized as experimental or nonexperimental. These designs can be used
to meet four key purposes. Experimental designs are used for the purpose of
examining causality. Nonexperimental designs can be used for the purposes
of describing a phenomenon in detail, explaining relationships and differ-
ences among variables, and predicting relationships and differences among
variables. The major difference between nonexperimental and experimental
designs is the role of the researcher. In experimental designs, researchers
actively manipulate the independent variable (IV), sometimes known as the
causal variable, to determine its effect on the dependent variable (DV), or
outcome variable. Experimental designs also involve randomization and the
use of a control group whose results can be compared to the group receiving
the experimental intervention. Quasi-experimental designs also involve the
manipulation of the IV but lack either randomization or a control group. In
nonexperimental designs, researchers are observers noting the occurrence of
the variables of interest and trying to determine relationships and differences.
Other quantitative designs are used to address methodological issues such as
instrument development or in the case of meta-analyses to examine outcomes
across a number of studies.
As you appraise an article for the quality of the study presented, you should
find that there is a logical flow of information presented. Information from the
literature reviewed and discussion of the study framework should lead you to
agree that the study is needed, that the purpose is appropriate given the litera-
ture presented, and that the planned design will be able to generate quantitative
information to address the stated research questions and hypotheses.Understanding Key Concepts
in Quantitative Designs
Best practice means that nurses must have confidence in the evidence that they
are applying to patient care. Having confidence in findings requires that nurses
be able to critically appraise quantitative studies before applying findings to
practice. Therefore, understanding key concepts and principles related to the
design of quantitative studies is necessary.FYI
An appropriate research design reflects an
integration of the theoretical and empirical
literature that was presented in the review
of the literature section of the study.150 CHAPTER 6 Key Principles of Quantitative Designs