Single Case Designs
for Clinicians:
Bridging the Gap Between
Science and Practice
Jennifer L. Villatte
University of Nevada, Reno
ACBS World Conference 2010
Workshop Objectives
• PART I:
– Fundamentals of Single Case
Designs
• PART II:
– Using SCDs in Case Formulation,
Treatment Planning, Progress
Monitoring
• PART III:
– Practical Applications: Designing
and implementing your study
CLINICAL
RESEARCH
CLINICAL
PRACTICE
How do I help
the most
people with
these kinds of
problems?
How do I help
this person
sitting in front
of me right
now?
Single Case Designs Bridge that Gap
Avoids
small,
unimportant
effects
Links science
to practice,
practice to science
Facilitates
innovation
Fits easily
into
clinical settings
Creative and
flexible
Benefits of Single Case Designs for
Clinicians and Clients
• Promotes working alliance
• Allows problems and solutions to be seen
from a different perspective
• May increase treatment efficiency and
effectiveness
• May enhance motivation for clinicians and
clients
• Logic closely parallels good clinical decision
making
Is one
treatment
better than
another?
Does
homework
make a
difference?
Is this
intervention
helping my
client?
Will group or
individual
work better
for this
client?
Which
problem do I
start with?
When should I
terminate?
Which EST
should I use for
this particular
client?
Which
component
do I start
with?
Is there a
more
efficient way
to deliver
treatment?
Single Case Design Essentials
SCDs are experimental, which means we must
consider:
• Internal Validity: Are effects due to intervention?
→ Adequate comparison conditions
• External Validity: Does this data generalize?
→ Replicate, replicate, replicate
This requires:
• Repeated, continuous measurement
• Systematic manipulation of intervention
Single Case Design
Essentials
Step 1: Choose a target behavior
Step 2: Measure it continuously
Step 3: Monitor target behavior
until stability is established
Step 4: Systematically apply or alter
treatment interventions
Choose
intervention
targets that are:
Frequent
Concrete and
quantifiable
Stable without
treatment
Establish a Stable Baseline
Repeatedly collect
measures to determine...
• Ideally, 3+ data points
• Withhold treatment
until baseline is stable
LEVEL
TREND
COURSE
Is this baseline stable?
Baseline
Intervention
Is it stable if I hoped to produce this?
Baseline
Intervention
What if I hoped to produce this?
Baseline
Intervention
What do I do if the target
behavior is not stable?
• Analyze sources of
variability
• Block or average data
• Wait until it becomes
stable
• Begin treatment
anyway
AaaarrrggghhhHHHH!!
Unstable Baseline Data
Percent Time On-Task
100
80
60
40
20
Average
Time
On-Task
for All
Children
in this
Classroom
Troublesome Days
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16
Days
Analyze Source of Variability
With-Mother Days
Percent Time On-Task
100
80
60
40
With-Father Days
20
0
1
2
3
4
5
6
7
8
9
Days
10 11 12 13 14 15 16
Behavior
Hard to
make sense
of this...
Raw Data
Sessions
Data Blocked Every Two Sessions
Behavior
With
blocking,
a pattern
emerges
Weeks
Next Step: Measure Continuously
Use as many measures as is
practical and meaningful
as often as is practical
and meaningful
using what is available
Self-report measures
Idiographic ratings
Diary cards
Collateral reports
Chart information
Treat design elements like building blocks
No-treatment assessment
(e.g., baseline, follow-up,
treatment breaks)
Treatment package
(e.g., ACT, DBT)
Treat design elements like building blocks
Delivery method
(e.g., group, individual)
Treatment components
(e.g., values, mindfulness)
Classic Design: The Reversal
Baseline
Intervention
Follow-Up
Assessment
without
treatment
Assessment
throughout
treatment delivery
Assessment
without
treatment
Classic Design: Alternating Treatments
Baseline
Treatment 1
Treatment 2
Treatment 1
Treatment 2
Assessment
without
treatment
ACT
CBT
ACT
CBT
Acceptance
Values
Acceptance
Values
Homework
No Homework
Homework
No Homework
Individual
Group
Individual
Group
Classic Design:
Multiple
Baselines
#1
• Across participants
with similar problems
#2
• Across behaviors
in the same participant
• Across treatment
processes or components
• Across settings or
#3
treatment modalities
Multiple Baseline
Across
Participants
#1
I have three clients with
mixed depression and
anxiety, as measured by
the DASS.
#2
All will receive ACT, but
they won’t begin
treatment at the same
time due to wait list.
#3
Multiple Baseline
Across
ACT Processes
I want to see if process
measures move when I
target specific ACT
processes with one
client.
According to my case
conceptualization,
1st Target mindfulness
2nd Target defusion
3rd Target values
FFMQ
#1
ATQ-B
#2
Values
Bullseye
#3
Choosing a DesignWhat questions do I have?
• Is treatment useful for a specific
problem/combination of problems?
• Is one treatment better than another?
• Which components contribute to efficacy?
• Does the order of components matter?
• What is the optimal level of treatment?
• Does the treatment generalize across contexts?
• What is the best way to train/deliver treatment?
• Will treatment gains maintain after termination?
Choosing a DesignWhat is possible with my caseload?
• How many clients do I have with similar
presentations?
• Can I collect baseline data and wait long enough
to establish stability?
• What is the nature of target behaviors?
• How often do I need to collect assessment
measures?
• Is it ethical to withdraw treatment?
• Can I switch treatments or treatment targets?
• Be curious- Play!
• Be creative with
design elements
• Be collaborative and
involve your client
• Be flexible and ready to change courselet the data guide you
• Be spontaneous- avoid excessively
preconceived designs; take advantage of
serendipitous events
Graphing and Organizing Data
100
80
60
40
20
0
1
2
3
4
5
6
7 8
9 10 11 12 13 14 15 16
Days
We Could Organize by Time...
100
80
60
40
20
0
1
2
3
4
5
6
7 8
9 10 11 12 13 14 15 16
Days
...And Then By Situation
Baseline
100
Intervention
80
60
40
20
0
1
2
3
4
5
6
7
8
9
10
Days
11 12 13 14 15 16
But in other situations we could
organize them by situation...
Baseline
100
80
60
40
Intervention
20
0
1
2
3
4
5
6
7
8
9
10
Days
11 12 13 14 15 16
...And Then By Time
Baseline
100
80
60
40
Intervention
20
0
1
2
3
4
5
6
7
8
9
10
Days
11 12 13 14 15 16
Analyzing The Data
• Statistical Methods
– Test for autocorrelation
– Compare the Means
– Test effect sizes
• Visual inspection of
level, course, trend
Sharing What You Learned
• Brief reports on Listservs
• Research-Practice networks
– PRACTICEground.org
– Behavioral Collective SIG
• Conference Presentations
• Scholarly Journals
• Behavior Modification
• Behavior Therapy
• Behavioural and Cognitive
Psychotherapy
• Clinical Case Studies
• Clinical Psychology: Science and
Practice
• Cognitive and Behavioral Practice
• Journal of Applied Behavior
Analysis
• Journal of Contextual Behavioral
Science
• Journal of Behavioral Therapy and
Experimental Psychiatry
Ethical Considerations
• Research vs. Treatment evaluation
– Do you intend to publish this information?
• Institutional Review Boards
• Informed consent
– Confidentiality
– Privacy
– Risk/Benefit Analysis
PART 2:
Single Case Designs
in case formulation,
treatment planning, &
progress monitoring
Case Formulation Approach
1. Start with a model of psychopathology
– Development
– Maintenance
– Treatment
2. Assessment of relevant targets
– Processes
– Outcomes
3. Case Formulation
4. Treatment Plan
5. Assess, Reformulate, Modify Treatment Plan
Case Formulation Approach
Treatment
Initiation
Treatment
Termination
Case
Formulation
Assessment
Treatment
Planning
Treatment
Implementation
Based on J. Persons, 2008
= Therapeutic Relationship
Example: The multi-problem client
• How do I know what to target at what time
with what technologies given multiple
treatment targets?
• How do I know if what I’m doing is effective,
given that these problems are known to be
slow to remit?
Initial Assessment
• Current diagnoses
– Borderline Personality Disorder
– Major Depression, Dysthymia
– Post Traumatic Stress Disorder
– Eating Disorder NOS
– Panic Disorder w/Agoraphobia
• Recent diagnoses
– Alcohol, Cocaine, Marijuana Dependence
– Bulimia Nervosa
– Obsessive Compulsive Disorder
Initial Assessment
• Treatment History
–
–
–
–
SSRIs (1 year)
Individual CBT (1.5 years)
Group CBT (4 weeks)
Alcoholics Anonymous (2 years)
Remember
Informed
Consent
• Presenting Problems: “I hate my life.”
– Emotional numbing/overwhelming dysphoria;
unstable sense of self; chronic emptiness; shame, selfdisgust, self-stigma; urges to use drugs and alcohol;
obsessions and ruminations; self-harm and suicidality;
binging and purging; avoidance: crowds, touch,
emotions; stagnation at school and work; lack of
motivation; social isolation/never had a romantic
relationship; chaotic family relationships
Choosing a Design
Subject 1
PLAN A:
Subject 2
Subject 3
PLAN B:
PLAN C:
A:
No Treatment
Baseline
A:
No Tx
Baseline
A:
No Treatment
Follow-Up
B:
Treatment
B:
Treatment
Phase #1
A:
No
Tx
C:
Treatment
Phase #2
A:
No Tx
Follow-Up
Case
Formulation
Dominance of the
Conceptualized Past and Feared
Future; Weak Self-Knowledge
Lack of Values
Clarity;
Dominance of
Pliance and
Avoidant Tracking
Experiential
Avoidance
Psychological
Inflexibility
Cognitive
Fusion
Inaction,
Impulsivity, or
Avoidant
Persistence
Attachment to the Conceptualized Self
Treatment
Planning
Present
Contact
with the
Moment
Present
Moment
Awareness
Values
Values
Clarification
and Induction
Acceptance
Experiential
Acceptance
Psychological
Flexibility
Defusion
Defusion
Committed
Committed
Action
Action
PRIMARY TARGETS
SECONDARY TARGETS
Self as
Self-as-Context
Context
Treatment Phase One
Problem
Process
Measure
Experiential Avoidance
Cognitive Fusion
Past/Future Dominance
Experiential Acceptance
Defusion
Present Moment Focus
Acceptance and Action Q
Automatic Thoughts Q
Five Factor Mindfulness Q
Goals:
– Reduce misery and increase behavioral stability
– Increase awareness, reduce reactivity
– Break up thought/action fusion (impulsivity)
– Reduce dominance of judgment and evaluation
PRIMARY PROCESS MEASURE:
ACCEPTANCE AND ACTION QUESTIONNAIRE
Range: 10-70
Higher scores= greater
psychological flexibility
80
70
NO
Tx
WEEKLY
TREATMENT
60
NO
Tx
WEEKLY
NO
TREATMENT Tx
BI-WEEKLY
TREATMENT
NO TREATMENT
Tx Terminated
50
40
Tx Initiated
30
20
10
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63
WEEKS
ATQ-B
Range: 30-150
Higher Score = Greater Distress
PROCESS MEASURE: DEFUSION
170
WEEKLY
TREATMENT
NO Tx
NO Tx
WEEKLY
TREATMENT NO Tx
BI-WEEKLY
TREATMENT
NO Tx
150
130
frequency
Tx Initiated
110
believability
90
Tx FOCUS=
DEFUSION
70
Treatment
Tx Terminated
Terminated
50
30
1
3
5
7
9
11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63
WEEKS
FFMQ: Range: 0-5; Higher scores = ↑ mindfulness
PROCESS MEASURE: MINDFULNESS
WEEKLY
TREATMENT
NO Tx
5
NO Tx
WEEKLY
NO Tx
TREATMENT
BI-WEEKLY
TREATMENT
NO Tx
Tx Targets:
Generalization,
Act with Awareness
4.5
4
3.5
3
Tx Targets:
Non-react,
Non-judge,
Observe
2.5
nonreact
nonjudge
observe
describe
act with awareness
2
1.5
1
1
3
5
7
9
11
13
15
17
19
21
23
25
27
WEEKS
29
31
33
35
37
39
41
43
45
49
53
57
61
Treatment Phase Two
Problem
Process
Measure
• Attachment to
Conceptualized Self
• Lack of Clarity/
Pliant/Avoidant Tacking
• Inaction/Impulsivity
Self-as-Context
Self Compassion Scale
Values Clarification
& Induction
Committed Action
Personal Values Q
Values Bullseye
Goals:
– Establish stable sense of self
– Increase motivation and contact with reinforcers
– Increase persistence in goal-directed behavior
– Increase sense of purpose and life satisfaction
PROCESS MEASURE-VALUES AND COMMITED ACTION
NO Tx
WEEKLY
TREATMENT
15
NO Tx
NO Tx
WEEKLY
TREATMENT
BI-WEEKLY
TREATMENT
Bulls-eye Range: 1-15
Higher scores= Values Consistent Action
NO Tx
Treatment
Terminated
13
11
9
Treatment
Initiated
VALUES
WORK
INITIATED
7
Personal Growth
5
Relationships
Leisure
3
Work/Education
1
1
3
5
7
9
11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63
WEEKS
PROCESS MEASURE: SELF AS CONTEXT
WEEKLY
TREATMENT
NO Tx
NO Tx
WEEKLY
NO Tx
TREATMENT
Self Compassion Scale
Difficulties in Emotion
Regulation Scale
BI-WEEKLY
TREATMENT
Range: 0-5
Higher scores =
better functioning
NO Tx
5
Tx Terminated
4.5
4
3.5
3
self
compassion
emotion
regulation
2.5
2
Tx Initiated
1.5
1
1
3
5
7
9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63
WEEKS
OUTCOME MEASURES- SYMPTOM INVENTORIES
4.00
NO Tx
WEEKLY
TREATMENT
NO Tx
WEEKLY
TREATMENT
NO Tx
BI-WEEKLY
TREATMENT
Range: BSI 0-5; BSL 0-4
Higher Score = Greater Distress
NO Tx
3.50
3.00
2.50
BSI global
severity index
Tx Initiated
Borderline
Symptom List
2.00
1.50
1.00
Tx Terminated
0.50
0.00
1
3
5
7
9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63
WEEKS
OUTCOME MEASURES- WHO QUALITY OF LIFE
6.00
WEEKLY
TREATMENT
NO Tx
NO Tx
WEEKLY
TREATMENT
NO Tx
BI-WEEKLY
TREATMENT
Range: 0-5
Higher scores=
better quality of life
NO Tx
5.50
5.00
4.50
4.00
3.50
physical
3.00
environment
2.50
social
2.00
psychological
1.50
1.00
1
3
5
7
9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63
WEEKS
Discussion
• Clinical: Treatment was effective.
– All measures below clinical levels at post-treatment
– Treatment gains maintained at 4-month follow up
• Research: Model was supported.
– Targeted techniques produced expected changes in
process measures
– Changes in hypothesized processes of change
preceded changes in outcome measures
PART III:
Practical Applications:
Designing and
Implementing Your Study
Consider Your Current Caseload
• What outcomes do you hope for?
– Behavior change
(frequency, form or situational sensitivity)
– Symptom reduction
– Quality of Life/Functioning
• What processes do you expect
to affect these outcomes?
– Based on your model
– What causes, maintains, or alleviates problems?
Consider Your Current Caseload
• How could you assess these?
– Idiographic self-monitoring, diary cards
– Standardized self-report measures
– Behavioral measures
• How often to take measures?
– How quickly do I expect
treatment targets to change?
– How often is feasible for my client?
What elements do you need to
build your study?
• No-treatment
assessment
• Treatment package
• Treatment processes
• Treatment components
• Delivery method
• Setting or context
Baseline
Intervention
FollowUp
Baseline
Treatment 1
Treatment 2
Treatment 1
Treatment 2
Assessment
without
treatment
ACT
CBT
ACT
CBT
Acceptance
Values
Acceptance
Values
Homework
No Homework
Homework
No Homework
Individual
Group
Individual
Group
You’ve got everything you need
But just in case you want more....
...some additional resources for
conducting Single Case Designs
Additional Reading
•
•
•
•
•
•
Barlow, D.H., Nock, M. K., & Hersen, M. (2008). Single Case Experimental
Designs: Strategies for Studying Behavior Change, 3rd edition. Allyn &
Bacon.
Hayes, S. C., Barlow, D. H., & Nelson-Gray, R. O. (1999). The Scientist
Practitioner, 2nd edition. Allyn & Bacon.
Kazdin, A. E. (2008). Behavior Modification in Applied Settings, 6th
edition. Wadsworth.
Hilliard, R. B. (1993). Single-case methodology in psychotherapy process
and outcome research. Journal of Consulting and Clinical Psychology, 61,
373-380.
Nugent, W. R. (2010). Analyzing single system design data. Oxford
University Press.
Persons, J. B. (2008). The case formulation approach to cognitivebehavior therapy. Guilford Press.
Examples of ACT SCDs
• Twohig, M. P., & Crosby, J. M. (2010). Acceptance and commitment
therapy as a treatment for problematic internet pornography viewing.
Behavior Therapy, 41, 285-295.
• Peterson, B. D., Eifert, G. H., Feingold, T., & Davidson, S. (2009). Using
Acceptance and Commitment Therapy to treat distressed couples: A case
study with two couples. Cognitive and Behavioral Practice, 16, 430-442.
• Jourdain, R. L., &Dulin, P. L. (2009). "Giving It Space": A case study
examining Acceptance and Commitment Therapy for health anxiety in an
older male previously exposed to nuclear testing . Clinical Case Studies, 8,
210-225.
• Stotts, A. L., Masuda, A., & Wilson, K. (2009). Using acceptance and
commitment therapy during methadone dose reduction: Rationale,
treatment description, and a case report. Cognitive and Behavioral
Practice, 16(2), 205-213.
Help with Graphing and Analysis
• Villatte’s Excel Scoring and Graphing Template for ACT measures
• Online SCD statistical analysis program- W. Paul Jones, UNLV
http://faculty.unlv.edu/pjones/singlecase/scsatool.htm
• Helpful papers on analyzing SCDs:
– Parker, R. I., & Vannest, K. (2009). An Improved Effect Size for Single-Case
Research: Nonoverlap of All Pairs. Behavior Therapy , 40,357-367.
– Solanas, A., Manolov, R., Onghena, P. (2010). Estimating slope and level
change in N = 1 designs. Behavior Modification, 34, 195-218.
– Kratochwill, T.R. & Levin, J.R. (2010). Enhancing the scientific credibility of
single-case intervention research: Randomization to the
rescue. Psychological Methods, 15, 124-144.
– Fisher, W. W., Kelley, M. E., & Lomas, J. E. (2003). Visual aids and
structured criteria for improving inspection and interpretation of singlecase designs. Journal of Applied Behavior Analysis, 36, 387-406.
Thank you!
Jennifer Villatte
jlvillatte@gmail.com
All of the following available at your request:
• Presentation notes
• ACT assessment measures
• Scoring and graphing templates
• SCD consultation
• Reprints of published ACT SCDs
• Reprints of articles mentioned in this presentation