Presentation of Moderator

8/3/2019 Presentation of Moderator

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QUANTITATIVE TECHNQUES

Presentation on:

Moderators and Mediators


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Types of variable

The classification of variable is done in 3

different ways:

1. The causal relationship

2. The design of the study

3. The unit of measurement


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From the viewpoint of causation

Investigating a causal relationship, four set of

variable may operate:

1. Change variable

2. Outcome variable

3. Variable that affect the link4. Connecting or linking variable


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Independent variable:

Dependent variable

Extraneous variable Intervening variable


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From the viewpoint of unit

measurement

There are two ways of categorizing variable:

Unit of measurement is categorical (as innominal and ordinal scale) or continuous innature (as in interval and ratio scales)

Unit of measurement is qualitative (as innominal and ordinal scales) or quantitative innature (as in interval and ratio scales).


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Categorical Variables

Categorical variable can be of three types:

Constant variable Dichotomous variable

Polytomous variable


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Categorical variable

Constant variable: can have only one value or category

Dichotomous variable: can be divided only into twocategories e.g: yes/no , good/bad , rich/poor

Polytomous variable: can be divided into more thantwo categories e.g: Religion (Christian, Muslim, Hindu);political parties (Labor, Liberal, Democrat); attitudes

(strongly favorable favorable, uncertain, unfavorable,strongly unfavorable)


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Continuous Variable

They have continuity in their measurement.

For example age, income and attitude score.


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Main theme of the Presentation

Differentiate between two often-confused

functions of third variables that are:- Moderator

- Mediator


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Moderator

A moderator is a qualitative (e.g., gender, race,

class) or quantitative (e.g., level of reward)

variable that affects the direction and/or

strength of the relation between an

independent or predictor variable and a

dependent or criterion variable.

A variable that shows how relationship of

interest change under different circumstances.


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Mediator

Mediator variable is one that explains the

relationship between the two other variables.

A variable that comes in between the othervariables and affect one another.


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Moderator andMediator are often use

interchangeably

It is not at all uncommon for social

psychological researchers to u, the terms

moderator and mediator interchangeably.

Example: Reuben M. Baron and David A.

Kenny criticized social researchers that they

use it interchangeably. Harkins and William

(1980), identified the impact of identifiabilityon social loafing by observing that it

moderates social loafing and within same

paragraph proposed that it is a important


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The Nature of Moderators

Moderator can be qualitative (gender, race,

class) or can be quantitative (level of reward)

It affect the direction between dependentvariable and independent variable

It affect strength of relationship between

dependent variable and independent variable


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The Nature of Moderators

That factor which is measured, manipulated,

or selected by the experimenter to discover

whether it modifies the relationship of the

independent variable to an observed

phenomenon. It is a special type of

independent variable.

The independent variable's relationship withthe dependent variable may change under

different conditions. That condition is the

moderator variable


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Example

Smoking

(Assumed cause)

IV

Cancer

(Assumed

effect)

DV

Age of person

(Moderator)


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Smoking

(Assumed cause)

IV

Cancer

(Assumed

effect)

DV

Duration of Smoking

(Moderator)


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Example of Moderator

Behavioral therapy works better for males and

cognitive therapy works better for females. In

this case, gender is the moderator variable.

The relationship be type of therapy

(behavioral versus cognitive) and

psychological relief is moderated by gender.


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Cognitive

Therapy (female)

Behavioral

Therapy (male)

PsychologicalRelief

Gender

(moderator)


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Diagrammatic display


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MEDIATORS

Mediator variables are also called

Intervening variables

Process variableConnecting variables

Linking variables

Intermediary variables


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In certain situations the relationship between

an IV and DV cannot be established without

the intervention of another variable.

Intervening variables link the IV and the DV.

Mediators give us information on why or bywhat mechanism X causes Y. while moderators

tell when and under what conditions X causes

Y.


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Example

Income longevity needs


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Intervening variables theoretically affect the

observed phenomenon but cannot be seen,

measured or manipulated; its affect must be

inferred from the effects of independent and

moderator variables on the observed

phenomenon.

E.g. A promotion campaign will increase thesavings activity, especially when free prizes are

offered. The results come from enhancing the

motivation to save.


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Path c'is called the direct effect. The

mediator has been called an intervening or

process variable. Complete mediation is the

case in which variable X no longer affects Y

after M has been controlled and so path c'is

zero.


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Note that a mediational model is a causal

model. For example, the mediator ispresumed to cause the outcome and not vice

versa.


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The general test for mediation is to examine

the relation between

the predictor and the criterion variables, the relation between the predictor and the

mediator variables,

and the relation between the mediator andcriterion variables.


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Mediation implies that the IV affects the

mediator, and then the mediator affects theDV.


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Example

educational level -----> occupational type -----> income level

employers will not pay you just because you

have a degree, in fact, it is the job you obtain

that pays the salary. The job is the intervening

or mediating variable between educational

level and income level.


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THANK YOU

Presentation of Moderator

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