• Definition: Variables are properties or characteristics
of people or things that vary in quality or magnitude
from person to person or object to object (Miller &
Nicholson, 1976)
Demographic characteristics
Personality traits
Communication styles or competencies
• in order to be a variable, a variable must vary (e.g.,
not be a constant), that is, it must take on different
values, levels, intensities, or states
• Variable: “any entity that can take on a variety of
different values” (Wrench et al, 2008, p. 104)
– gender
– self-esteem
– managerial style
– stuttering severity
• attributes, values, and levels are the variations in a
– Attribute: political party:
– Value: Democrat, Republican, Independent, etc.
– Attribute: Self-esteem
– Level: High, Medium, Low
independent variable
• the variable that is manipulated either by the
researcher or by nature or circumstance
• independent variables are also called “stimulus”
“input” or “predictor” variables
• analogous to the “cause” in a cause-effect
“operationalization” of the
independent variable
• Operationalization:
translating an abstract
concept into a tangible,
observable form in an
• Operationalizations can
– variations in stimulus
conditions (public schools
versus home schooling)
– variations in levels or
degrees (mild vs. moderate
vs. strong fear appeals)
– variations based on
standardized scales or
diagnostic instruments (low
vs. high self esteem scores)
– variations in “intact” or
“self-selected” groups
(smokers vs. non-smokers)
varieties and types of variables
Discrete variables
– Nominal variables: distinct, mutually
exclusive categories
• religions; Christians, Muslims,
Jews, etc.
• occupations; truck driver, teacher,
• marital status; single, married,
– Concrete versus abstract variables
• concrete; relatively fixed,
– biological sex
– ethnicity
• abstract; dynamic, transitory
– mood, emotion
– occupation
– Dichotomous variables:
• true/false, female/male,
– Ordered variables: mutually exclusive
categories, but with an order,
sequence, or hierarchy
• fall, winter, summer, spring
• K-6, junior high, high school,
varieties and types of variables-continued
• Continuous variables: include constant
increments or gradations, which can be
arithmetically compared and contrasted
– IQ scores
– self-esteem scores
– age
– heart rate, blood pressure
– number of gestures
Unit of analysis
Definition: The specific entity being
– individual; self esteem, fluency
– dyad: self disclosure, touch
– group: roles, norms
– Organization: communication
networks, upward-downward
– Culture: individualism vs.
What constitutes a specific score or
measure on the outcome variable?
– marital satisfaction?
– one row of data in SPSS
Ecological fallacy: drawing
conclusions about individuals
based on group data
committing a “sweeping
generalization” about participants
in a research study
– individualism/collectivism
– all southerners are bigots
• definition: the specific steps or procedures
required to translate an abstract concept into a
concrete, testable variable
– example: high versus low self-esteem (split-half or
top vs. bottom third?)
– example: on-line versus traditional classroom (how
much e-learning constitutes an “on-line” class?)
examples of operationalizations
• credibility (high versus low)
• culture/ethnicity (self-report)
• type of speech therapy (inclinic vs. at school, vs. at
• compliance-gaining strategy
preferences (positive versus
negative, self-benefit versus
other benefit)
• “powerless” language style
• fear appeals (mild, moderate,
• food server touch versus no
dependent variable
• a variable that is observed or measured, and that
is influenced or changed by the independent
• dependent variables are also known as “response”
or “output” or “criterion” variables
• analogous to the “effect” in a cause-effect
confounding variable
• also known as extraneous variables or intervening
• confounding variables “muddy the waters”
• alternate causal factors or contributory factors which
unintentionally influence the results of an experiment,
but aren’t the subject of the study
mediating variable
• a.k.a. moderating, intervening, intermediary, or mediating
• a 2nd or 3rd variable that can increase or decrease the
relationship between an independent and a dependent variable.
• for example, whether listeners are persuaded more by the quality
or quantity of arguments is moderated by their degree of
involvement in an issue.
interchangeability of independent and
dependent variables
• The same concept or construct could serve as the
independent variable in one investigation, and the dependent
in another.
• example: “source credibility”
– as an independent variable; RQ: Does source credibility (low versus
high) have a significant effect on attitude change?
– As a dependent variable; RQ: Does the amount of evidence contained
in a speech affect listeners’ perceptions of the source’s credibility?
• example: “fetal alcohol syndrome” (FAS)
– As an independent variable: RQ: Does severity of FAS correlate
positively with language delay in infants?
– As a dependent variable: RQ: Does the amount of maternal alcohol
use correlate positively with the severity of FAS in infancy?
Relationships among variables
• Differences
– Differences in kind, degree
• Relationships (correlations)
– Positive correlation
– Negative correlation
– No or neutral correlation

Variables PPT - California State University, Fullerton