Class 6 2016
Between Group Designs, Expo
Facto Designs, Status Variable
Within Groups Designs
Heppner 2015 - Ch.11
Chapters HWK 7 (146-163),10 (224233, 243-4) 12(308) ANOVA PDF
Between Group Design
Therapy Outcome Research
Purpose
Independent Variable
Assignment to
Groups
Treatment Delivery
Participant Selection
Control Group
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Between Group Design: Experimental
Therapy Outcome Research
Compare treatment groups
under tightly controlled
conditions
Independent Variable Highly specified; manipulated;
categorical
Assignment to Groups Random; stratified; each
participant only 1 treatment
Closely monitored
Treatment Delivery
Purpose
Participants
Control Group
Highly selective
No-treatment/Placebo, or
Other Active Treatment
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External and Internal Validity
E I
Experimental
Field
e I
E i
Correlational/
Descriptive
Field
Clinical
Trials
e i
Experimental
Laboratory
Correlational/
Descriptive
Laboratory
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Between Group Design
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Expo Facto:
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IV is a status variable (not manipulated)
Factorial Design:

More than one IV (Experimential or Expo-facto)
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Within Group Design: Experimental
Therapy Outcome Research
Purpose
Independent
Variable
Assignment to Groups
Treatment Delivery
Participants
Control Group
Compare treatments under tightly
controlled conditions
Highly specified; manipulated;
categorical
Randomize the sequence of
treatment delivery; each
participant receives all treatments
Closely monitored
Highly selective
Active Treatments
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Does loud noise affect short term memory? –
Within Subjects Variable
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Advantages of Pre-Test


Select participants; describe groups
Use as a covariate when comparing posttest means
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Comparing gain scores is not recommended
(p.153)
Compare drop-outs and completers in initial
severity
Use as post-test for early terminators in
“intent to treat” analyses
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Treatment Study: Question 6

Research Design

Independent Variables

Dependent Variables

Participants
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Treatment Study: Question 6
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Research Design
1
2
3
4
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Independent Variables (Main Effects)
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Treatment Study: Question 5
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Research Design
1 Experimental
2 BW-groups
3 Pre-Test--Posttest
4 Factorial
Independent Variables (Main Effects)
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Treatments: CBT Cult. Infused vs. Standard
Therapist Ethnicity: Latino/a vs. White

In this study, is ethnicity a true IV or a status
variable? Why?
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Study Description

A study examined the effectiveness of two treatments ----CBT culturally infused treatment vs. CBT treatment
as usual -- for depression of 60 Latina/o participants.

The treatments were delivered by either a Latino
therapist (half of the sample) or a White therapist (to
the other half).

Participants were randomly assigned to
 the type of treatment and
 the therapist’s ethnicity conditions.
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Treatment Study: Question 6
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Dependent Variable(s)
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
Independent Variable(s)
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
Participants

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Treatment Study: Question 6
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Dependent Variable(s)
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
Independent Variable(s)
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

BDI– Continuous
Treatment: CBT Culturally Infused –CBT
Standard
Therapist Ethnicity
Participants

30 Males & 30 Females (not related)
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Treatment Study: Question 5(b)

Potential research questions regarding
treatment effectiveness
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Question 1:

Question 2:
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Question 3:
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Treatment Study: Question 5(b)

Potential research questions regarding
treatment effectiveness
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Question 1:Main Effect Treatment Group
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Question 2:Main Effect Therapist Ethnicity
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Question 3: Moderation Effect
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Treatment X Therapist Ethnicity
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Analyses - Questions
Means
Means
Main Effect Treatment Infused Treatment
Usual Treatment
Main Effect
Therapist Ethnicity
Anglo
Latino
Treat x Th. Ethnicity
Inf Treat. Anglo T
Usual Treat Anglo T
Inf. Treat. Latino T
Usual Treat Latino T
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Question 1 Main Effect Treat.

Do participants in the Culturally Infused
Treatment (T1) obtain lower post-test
depression scores than participants in the
Treatment as Usual (T2) ?
Tx 1 Infused
Tx 2 Usual
Mean = 7.9**
Mean = 12.2
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Question 2 Main Effect- T. Eth.

Do participants who had a Latino Therapist
obtain lower post-test depression scores in
parenting skills than participants who had an
Anglo Therapist
Latina/o Th
Anglo Th
Mean = 8.5ns
Mean = 8.4
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Question 3 Moderation

Does Therapist ethnicity moderate the
association of type of treatment to
depression scores?
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Among participants with Latino/a TH:

Among participants with Anglo TH:
Treatment 1
Infused
Treatment 2
Usual
Latina/o
Mean = 7.4*
Mean = 10.1
Anglo
Mean = 7.0*
Mean = 9.7
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2X2 ANOVA with Moderation
Covariate
Depression
Moderator: Therapist Ethnicity
DV
IVs
Treatment
Post Test Parental Skills F statistic
Scales
Main
2 Means
Treat. I vs. Treat 2 Effect *
Therapist
Ethnicity
Main
Anglo vs. Latino/a Th Effect ns
Treatment X
Therapist
Ethnicity
4 Means
2 Means
Th Anglo: T1 vs. T2
Th Latino/a: T1 vs. T2
Interaction
Effect
?
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Question 3 Moderation

Does Therapist ethnicity moderate the association of
type of treatment to Depression scores?
 Among participants with Latino/a TH: do
participants in T1 obtain lower depresion scores than
those in T2?
 Among participants with Anglo TH: do participants
in T1 obtain lower depression scores than those in
T2?
Therapist
Treatment 1
Infused
Treatment 2
Usual
Latina/o
Mean = 7.4*
Mean = 10.1
Anglo
Mean = 7.0*
Mean = 9.7
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2X2 ANOVA with Moderation
DV
Post-Test Depression Scale
Covariate Pre-Test Depression Scale
DV
IV
Treatment
Post Test Parental Skills F statistic
Scales
Main
2 Means
Treat. I* vs. Treat 2 Effect *
Therapist
Ethnicity
Main
Anglo vs. Latino/a Th Effect ns
Treatment X
Therapist
Ethnicity
4 Means
2 Means
Th Anglo: T1* vs. T2
Th Latino/a: T1* vs. T2
Interaction
Effect ns
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Table 1 Main Effects
Means Post-Test Depression Scale
Effects
Post-Test Depression Scale
Mean
Mean
F
value
Main:
Treatment
Infused Treatm.
Usual Treatm.
7.9*
12.2
*p<.05
Main
Therapist
Ethnicity
Latino/a Th.
8.5
Anglo Th.
8.4
NS
Interaction
Treat X Th Eth
Infused Treat
Latino/a 7.4*
Anglo 7.0*
Infused Treat
10.1
9.7
NS
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Results showed

A main effect for treatment
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No main effect for therapist

Therapist ethnicity did not moderate the
effect of treatment on depression post-test
scores


for the White therapists, Infused T>Usual T
for Latino/a therapists, Infused T>Usual T
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Does Therapist Ethnicity moderate the
treatment difference in depression?
NO
Therapists’ ethnicity did not matter: with
both types of therapists, participants in
culturally infused treatment obtained
lower post-test depression scores than
participants in usual treatment.
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Conclusion

If interaction effect(s) is present, related
main effect(s) is (are) not interpreted.

In this case, should we interpret the
treatment main effect?
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Conclusion

If interaction effect(s) is present, related
main effect(s) is (are) not interpreted.

In this case, should we interpret the
treatment main effect?
Yes, because there is no moderation
effect for Therapist ethnicity
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Table 1A Main & Interaction Effects
Means Post-Test Depression Scale
Effects
Post-Test Parenting Scale
Mean
Mean
F
value
Main:
Treatment
Infused Treatm.
Usual Treatm.
7.9*
12.2
*p<.05
Main
Therapist
Ethnicity
Latino/aTh.
8.5
Anglo Th.
8.4
NS
Interaction
Treat X Th Eth
Infused Treat
Latino/a 7.4ns
Anglo
8.0*
Usual Treat
7.3
7.0
*p<.05
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Conclusion
Regarding Table 1A, should we interpret
the treatment main effect?
NO, because there is a moderation
effect for Therapist ethnicity
Results show that
for Latino Th – no effect for treatment type
For Anglo Th- Infused T >Usual T

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Post Hoc Research Question

Research Design

Independent Variables

Dependent Variables

Participants
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Post Hoc Research Question

Research Design


Independent Variables
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
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Non-experimental; Factorial Between Groups
Treatment: Experimental
Gender: Status
Dependent Variables

Parental Skills
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Analyses - Questions
Means
Means
Main Effect T
Treatment
Infused Treatment
Usual Treatment
Main Effect
Participant Gender
Men
Women
Treat x P. Gender
Inf Treat. Men
Usual Treat Men
Inf. Treat. Women
Usual Treat Women
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Survey
Design
Correlational & Factorial
Expo-Facto Designs
o Document
nature or
frequency of a
variable
o Association of continuous
variables or of status
categorical variable(s) (IV)
to continuous variable(s)
o Descriptive:
o Test Hypotheses
No theoretical or o Theoretical/empirical rational
logical rational
needed
o Probability
samples
o Tolerant of convenience
samples
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Research Proposal Process
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Describe research interests in broad terms.
Identify testable research question(s)
Identify variables/constructs embedded in the
question.
Provide conceptual definitions for variables.
Provide operational definitions for variables
Develop a conceptual framework for
proposed study
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Conceptualizing a Research
Question

Three steps


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What do we know about the issue.
What we do not know about the issue.
How will the study bridge the gap.
How what we know leads to the
questions in my study
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