Defining Abstract Concepts: Constructs, Variables, and Operationalization, Schemes and Mind Maps of Communication

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CONSTRUCTS, VARIABLES,

AND OPERATIONALIZATION

July 5, 2011 Amanda Leggett

Outline

 Understanding CONSTRUCTS

 Understanding the importance of OPERATIONAL DEFINITIONS

 Understanding VARIABLES

Researchers define constructs both

“conceptually” and “operationally”

Conceptual definition : provides meaning to one construct in abstract or theoretical terms

BUT… We have to make our abstract concepts concrete so we can study them!

Operational definition : defines a construct by specifying the procedures used to measure a construct.

“the assignment of numerals to objects, events”

(What does it mean?)

(How to measure it?) Two ways to do this: --Providing a clear definition --Designating a particular measurement instrument to represent the concept

Intelligence:

Examples of definition

The capacity for abstract thought, understanding, communication, reasoning, learning, planning and problem solving.

Is intelligence related to happiness?

Intelligence: The score resulting from performing the Raven’s Progressive Matrices Test.

Conceptual:

Operational:

http://chap.hhdev.psu.edu/demo2/menu.aspx

Example

• Ex. 1: We are interested in the relationship between childhood depression and the divorce of one’s parents during childhood…
• Divorce
• Depression
• Ex. 2: Aggression in adults

Note…

 Operational definitions aren’t always good… they may not accurately capture the intended construct (i.e., lack validity)

 An operational definition is simply how a researcher decides to measure (and thus define) a construct

 For example, intelligence is more than a score on a test…

VARIABLES

 When we operationalize a concept, we are creating VARIABLES!

 Definition: Any characteristic that varies (meaning it must have at least two values)  Any event, situation, behavior, or individual characteristic that varies

Variables Examples

 Examples:

 Height (participant or subject variable)  Age (participant or subject variable)  Stress (response variable)  Score on depression test (response variable)  Number of bystanders to an emergency (situational variable)

Variables

 Research questions and hypotheses consist of x and y variables

 Is X related to Y?

 Is studying related to school performance?

Independent vs. Dependent

 Independent variable (IV)– the “x” variable  Considered the “cause” of a behavior (the DV)  Variable that is manipulated in experimental design  The predictor variable in an observational/correlational study

 Dependent variable (DV)– the “y” variable  The variable that is the “effect”  The “outcome” or “response” variable  The outcome variable in an observational/correlational study

Ask yourself: Which (do you think) comes first?

Example…

Is stress related to health?

Operational Definition (how to measure it?):

Stress: Emotional and physiological response to public speaking;

The score on the Perceived Stress Scale.

X Y

Conceptual (what does it mean?):

Stress: Emotional and physical strain that results when a

person is confronted with a threat or challenge that exceeds their coping ability.

Trier Stress Test:

Some individuals in the experiment have to give an impromptu speech!

Other individuals in the experiment have do something less stressful…

The researcher controls the level of stress in participants

Let’s say we operationalize Stress as the score on the Perceived Stress Scale.

Let’s say we operationalize Health by the measurement of an individuals’ blood pressure after sitting quietly for 5 minutes.

What type of X variable is perceived stress?

What type of Y variable is blood pressure?

Predictor (not under researcher control)

Outcome (because X is a Predictor variable)

Let’s say we operationalize Stress by whether participants had to give a public speech

Let’s say we operationalize Health by the measurement of an individuals’ blood pressure after giving the speech.

What type of X variable is public speaking?

What type of Y variable is blood pressure?

Independent (under researcher control)

Dependent (because X is independent variable)