The terms dependent
and independent variable apply
mostly to experimental research where some variables are manipulated,
and in this sense they are "independent" from the initial reaction
patterns, features, intentions, etc. of the subjects. Some other variables
are expected to be "dependent" on the manipulation or experimental
conditions. That is to say, they depend on "what the subject will
do" in response. Independent variables
are those that are manipulated whereas dependent
variables are only measured or registered.
Somewhat contrary to the nature of this distinction, these
terms are also used in studies where we do not literally manipulate independent variables, but only assign
subjects to "experimental groups" based on some preexisting
properties of the subjects. For example, if in an experiment, males are
compared with females regarding their white cell count (WCC), Gender could
be called the independent variable
and WCC the dependent variable.
vs. Independent Variables for more information.