variables
DESCRIPTION
VARIABLES. VARIABLES. Definition: Variables are properties or characteristics of people or communication phenomena that take on different values demographic characteristics personality traits communication styles or competencies constructs - PowerPoint PPT PresentationTRANSCRIPT
VARIABLESVARIABLES
VARIABLESVARIABLES
• Definition: Variables are properties or characteristics of people or communication phenomena that take on different values demographic characteristics
personality traits
communication styles or competencies
constructs
• 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
Variables Must Vary!
• “Female” is not a variable; if everyone in a study is female, then “female” is a constant.– female versus male is a variable– degree of femininity is a variable– females’ sexual orientation is a variable
DEFINITIONSDEFINITIONS
• 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 variable (p. 106)– Attribute: political party:
– Value: Democrat, Republican, Independent, etc.
– Attribute: Self-esteem
– Level: High, Medium, Low
INDEPENDENT VARIABLEINDEPENDENT VARIABLE
• the variable that is manipulated either by the researcher or by nature or circumstance (pp. 108-110)
• independent variables are also called “stimulus” “input” or “predictor” variables
• analogous to the “cause” in a cause-effect relationship
“operationalization” of the independent variable• Operationalization:
translating an abstract concept into a tangible, observable form in an experiment (pp. 178-179)
• Operationalizations can include:– 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 (single parent vs. dual parent households)
TYPES OF VARIABLES
• Discrete variables– Nominal variables:
distinct, mutually exclusive categories (p. 111)
• religion; Buddhists, Christians, Jews, Muslims, etc.
• occupation; truck driver, teacher, engineer
• marital status; single, married, divorced
– Concrete versus abstract variables (p. 104)
• concrete; relatively fixed, unchanging
• biological sex
• ethnicity
• abstract; dynamic, transitory
• mood, emotion
• occupation
• social media use
varieties and types of variables--continued
– Dichotomous variables:
• true/false, female/male, democrat/republican
– Ordered variables: mutually exclusive categories, but with an order, sequence, or hierarchy (p. 111-112)
• fall, winter, summer, spring
• K-6, junior high, high school, college
• Continuous variables (interval and ratio): include constant increments or gradations, which can be arithmetically compared and contrasted (pp. 113-115)
– IQ scores
– self-esteem scores
– age
– heart rate, blood pressure
– frequency of touch
UNIT OF ANALYSIS
• Definition: The specific entity being examined (p. 105)– individual; self esteem,
fluency– dyad: self disclosure, touch – group: roles, norms– organization: communication
networks, upward-downward influence
– culture: individualism vs. collectivism
• 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– all Asians are collectivistic– all southerners are bigots– all Catholics oppose gay
marriage
OPERATIONALIZATION
• 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 (the amount of online instruction that constitutes an “on-line” class)
examples of operationalizations
• credibility (high versus low)
• culture/ethnicity (self-report)
• type of speech therapy (in-clinic vs. at school, vs. at home)
• compliance-gaining strategy preferences (positive versus negative, self-benefit versus other benefit)
• “powerless” language style
• fear appeals (mild, moderate, strong)
• food server touch versus no touch
DEPENDENT VARIABLEDEPENDENT VARIABLE
• a variable that is observed or measured, and that is influenced or changed by the independent variable
• dependent variables are also known as “response” or “output” or “criterion” variables
• analogous to the “effect” in a cause-effect relationship
CONFOUNDING VARIABLECONFOUNDING VARIABLE
• also known as extraneous variables or intervening variables (p. 110, p. 267)
• 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 variables
• 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