purposes. These designs are often used to assess current practice. They can also
be used in the early stages of theory development. Conceptual and operational
definitions of the variables and possible theoretical relationships among the
variables can emerge from descriptive studies. Although most descriptive
designs tend to be cross-sectional, they can be conducted in any of the time
dimensions as discussed previously.
Descriptive designs are often called by a variety of names, such as explor-
atory, comparative, and survey designs. The term exploratory is used because
descriptive designs are used when little is known about a phenomenon, so
exploration is required. For example, an exploratory design could be used to
determine factors associated with nurses’ willingness to discuss sexual concerns
with their patients. The term comparative is used if the purpose of the study
is to describe phenomena by comparing two or more groups or two or more
variables. For example, a researcher could use this type of design to describe
nurses’ willingness to discuss sexual concerns with patients and compare
oncology nurses to cardiology nurses. Another approach a researcher might
take could be to study oncology nurses and compare their willingness to dis-
cuss sexual concerns with patients to variables such as the nurses’ ages, levels
of education, and years of experience. The term survey is used to indicate that
data are obtained through subjects’ self-report about variables such as their
attitudes, perceptions, and behaviors. Surveys and questionnaires are popular
methods used to collect descriptive data. They can be completed face to face,
through the mail, online, or through telephone interviews.
A well-controlled descriptive study offers a number of advantages over other
types of quantitative designs. Descriptive designs have flexibility in the methods
that can be used to collect data, often leading to more rapid collection of data
and cost savings. The major disadvantage of this type of design is the inability
to establish causality.Correlational Designs
Correlational designs are used when researchers are interested in establishing
relationships between two or more variables. When reviewing the evidence
from correlational studies, it is important for nurses to remember that cor-
relation does not prove causality. Because correlational designs do not involve
manipulation of the IV, no causal statements can be made. For example, for
some individuals there is a correlation between their symptoms of arthritis and
changes in the weather. Before a change in weather, individuals may experience
joint pain. However, one cannot conclude that joint pain causes the weather to
change even though there is a strong correlation between the two phenomena.
The best way to interpret a correlation is to understand that correlations simply
mean that the variables covary—that is, when there is a change in one variable,KEY TERMS
exploratory
designs:
Nonexperimental
design type used
when little is
known about a
phenomenon
comparative
designs: Descriptive
design type that
compares two or
more groups or
variables
survey designs:
Descriptive design
type involving data
obtained through
subjects’ self-report
correlational
designs:
Nonexperimental
designs used to
study relationships
between two or
more variables
covary: When
change in
one variable is
associated with
change in another
variable182 CHAPTER 7 Quantitative Designs: Using Numbers to Provide Evidence