Discussion: Variable Definition and Measurement
There are two familiar sayings in the research community. First, We live in a multivariate world, so we need to conduct multivariate research, and second, garbage in, garbage out. The
first statement is a reflection of the normal state of the human
condition, in which multiple factors usually influence a given
phenomenon. Stated in research terms, at least several variables are
related to the primary variable of interest. How, then, do you know
which variables to study? For example, when conducting depression
research with the elderly, some of the highly related variables that
also should be included in a primary depression study might include
physical health status, socialization, stress, coping, and access to
resources. No one variable on its own can explain depression in this
The second statementgarbage in, garbage outis
common in the quantitative statistical community and is
self-explanatory. If the quality of the measures and collected data are
poor, every action and result that follows will also be poor, thus
affecting reliability, validity, and credibility in a negative way.
Optimally designed and executed survey studies prioritize measurement.
They are reliable, meaning measurement is consistently applied. They are
also valid, meaning truth and meaning in the measurement is applied.
Finally, they are credible, meaning the results are subjectively, as
well as objectively, believable.
Refer back to the example in the Introduction
for this week. Using a depression scale that consistently measures the
specific construct of depression similarly with multiple measurement
points and samples strengthens reliability. Using an instrument that
measures the construct of depressionand not a similar construct such as
grief, stress, or anxietystrengthens validity. Ensuring that your
results relate to similar findings supported in the literature as well
as within the community that works with depression in older adults also
For this Discussion, use your topic from Week 3,
and consider three key variables in the research study you proposed for
that topic. Think about how you would operationally define and measure
each, using theory as the basis of your decisions. In addition, reflect
on how you would justify your choice of measurement, including specific
scales or measures you would use, and why. Finally, consider how a
multivariate approach to variable selection and measurement would
optimally assess your research problem.
With these thoughts in mind: