Class 7: Moderation and

Mediation

Momtraz et al (2012); Tram & Cole (2000)

Momtaz et al 2012: Variables

Control Vs IVs DV

Momtaz et al 2012: Variables

Control Vs IVs DVs

Age Chronic Medical Conditions

Well Being

Sex Personal religiosity (M)

Marital Status Social Religiosity (M)

EducationEmployment Status

Household Income

Place of Residence

Living Arrangement

Family Size

Momtaz et al 2012: Variables

Religiosity

Personal Social

• Faith/conviction • Self-centered goals

• Commitment to beliefs

• Social standing

• Meaning thru religion

• Support

Moderation Analyses: Regression

Medical Condition Wellbeing

Religiosity

Med R

Low R

High R

Table 3: Moderator: Religiosity/ DV:

Wellbeing

n = 1,410 R2 = .10** Δ R2 =.02** Δ R2 =.05**

Δ R2 =.01**

Momtaz et al 2012: Reg. 3rd Step

Control Vs IVs DVsAge Chronic Medical

Conditions Range 0-16

Well Being

Sex + F=0

Personal religiosity + (M)

Marital Status + M =1

Social Religiosity + (M)

EducationEmployment Status

Household Income +

Place of Residence

Living Arrang. - Sp.Ch/GCh = 1

Family Size

Moderator: Social Religiosity

Moderator: Personal Religiosity

Tram & Cole (2000)

• Self perceived Competence and the Relation between Life Events and Depressive Symptoms in Adolescence: Mediator or Moderator

Moderation Analyses: Regression

Negative Events (+)* Depression

Self-P Competence

r r r (+) (+)

Med SC

High SC

Low SC

Self-Competence- Moderator

• Negative Event: Bad gradeo High self competence - Attribute to effort

– something I can change ------- Work harder

o Low self-competence – Confirm belief, I am not capable, not changeable ------- Hopelessness

Table 2 – Page 756

Page 756—Left Bottom

What is different here from Table 2 on page

756? Table 2: Self Competence as a Moderator of the Relation of Negative Events to Depression Symptoms (at Time 2) (N=468)

Predictor measures

B SE B

ΔR2 R2

STEP 1 .29** .29**

Depression Time1 .36  .05 .38***

Gender   -.03  .06 -.02 

Negative events .10  .03 .14**

Self-Competence T1 -.19 .06 -.20**

Step 2 .002 .29002**

Events X Self-Comp. .08 .05 .07

** p <.001 Interactions involving gender were non-significant

p. 756- had power to detect a moderate interaction effect of ΔR2 = .02

Self-Competence as Mediator

• Developmentally, negative events help shape the child’s sense of self competence

• Previous research has shown that:o Neg Ev are +ly related to Depressiono Neg Ev are –ly related to Self Competence ando Low Self Competence is +ly related to

Depression o Does the magnitude and/or strength of the

relation of childhood neg events to Depression changes in the presence of Self-Competence?

21

The Mediational Model: Controlling for Depression T1 and Gender

Depression

Self-Competence

Negative

Events C

Test 1: Is the predictor related to the DV (Depression) —Controlling for Depression T1 and Gender ?

Test 2: Is the predictor (Negative Events) related to the Moderator (Self-C T2 is the DV)Controlling T1 and Gender ?

Test 1: Is the predictor related to the DV Depression T2Controlling for Depression T1 and Gender ?

Test 3 Is Mediator (Self-C) still related to the DV --Depression T2 -- when controlling for predictor (N. Events)?

Test 4: Relation of Predictor to DV diminishes or disappears in presence of mediator

24

The Mediational Model: Controlling for Depression T1 and Gender

Depression

Self-Competence

Negative

Events C =.20**

Sobel TestDescription of numbers needed

a = raw (unstandardized) regression coefficient for the association between IV and mediator. Table 4 -.19sa = standard error of a Table 4 .03

b = raw coefficient for the association between the mediator and the DV (when the IV is also a predictor of the DV). Table 5 - .22sb = standard error of b. Table 5 - .05

Sobel test equation z-value = a*b/SQRT(b2*sa

2 + a2*sb2) = 3.20 p<.01

Sobel Test Calculator

http://quantpsy.org/sobel/sobel.htm