Transcript Slide 1

Advancing the Science of Behaviour
Change
Susan Michie
Professor of Health Psychology
University College London
UK
Connecticut, USA: September 2010
Starting point …
• Interventions to change health-related behaviours
– amongst the general population, patients and health
professionals
• have had variable success.
• Behaviour change remains a formidable challenge
– we lack a clear understanding of
• effective techniques and
• mechanisms of change
• across behaviours, populations and settings.
To develop more effective interventions …
We need to improve our scientific methods in the following
areas:
1. Specify intervention content in sufficient detail in trial protocols and
published reports to allow accurate replication and evidence
syntheses that can identify “active ingredients” within interventions.
2. Apply theories of behaviour change to intervention development
and evaluation, and to evidence syntheses
• allows questions to be answered about not just “what worked” in
interventions but “how they worked”.
3. Match behaviour change techniques to mechanisms of action to
inform theory-based intervention development and evaluationbased theory development.
4. Define the extent to which interventions, and comparison
conditions, use theory and evaluate how this relates to
effectiveness.
5. Develop a model of behaviour as a starting point for systematic,
theory-based intervention development.
1. Specifying interventions more precisely
• Interventions often “complex”
– several, potentially interacting, techniques
• Poorly described
– Interventions often described vaguely
e.g. “behavioural counselling”
– Where protocols with more detail are
available, terminology is variable
• Impedes replication, implementation,
evidence synthesis
Guidelines for specifying interventions
• CONSORT guidelines for reporting RCTs
– Evaluators should report “precise details of interventions [as]
actually administered” Moher et al, 2001
• Which precise details?
–
–
–
–
–
–
–
–
the content or elements of the intervention
characteristics of those delivering the intervention
characteristics of the recipients,
characteristics of the setting (e.g., worksite)
the mode of delivery (e.g., face-to-face)
the intensity (e.g., contact time)
the duration (e.g., number sessions over a given period)
adherence to delivery protocols
Davidson et al, Annals of Beh Med, 2003
Example of the problem: Descriptions of
“behavioural counselling” in two interventions
Title of journal article
Description of “behavioural
counseling”
The impact of behavioral
counseling on stage of change fat
intake, physical activity, and
cigarette smoking in adults at
increased risk of coronary heart
disease
“educating patients about the
benefits of lifestyle change,
encouraging them, and suggesting
what changes could be made”
Effects of internet behavioral
counseling on weight loss in
adults at risk for Type 2 diabetes
“feedback on self-monitoring
record, reinforcement,
recommendations for change,
answers to questions, and general
support” (Tate et al. JAMA 2003)
(Steptoe et al. AJPH 2001)
Biomedicine vs behavioural science …
example of smoking cessation effectiveness
Varenicline JAMA, 2006
• Intervention
content
• Mechanism of action
– Activity at a subtype of the
nicotinic receptor where its
binding produces agonistic
activity, while simultaneously
preventing binding to a4b2
receptors
Behavioural counselling
Cochrane, 2005
• Intervention content
– Review smoking history &
motivation to quit
– Help identify high risk situations
– Generate problem-solving
strategies
– Non-specific support &
encouragement
• Mechanism of action
– None mentioned
To improve development and application of
interventions to change behaviour ….
• Need a reliable method for describing intervention
content in terms of
– distinct component techniques
– standardised language
• An example developed from 3 systematic reviews
of “self-management” interventions to increase
physical activity and healthy eating
– A 26 item taxonomy
Abraham & Michie (2008). A taxonomy of behavior change techniques used in
interventions. Health Psychology.
Behaviour change techniques: reliable taxonomy
to change physical activity and healthy eating behaviours
Involves detailed planning of what the person will do
including, at least, a very specific definition of the
behaviour e.g., frequency (such as how many times a
15. (e.g.,
General
encouragement
day/week), intensity
speed)
or duration (e.g., for how
General information
long for). In addition,
at least one ofrewards
the following contexts
16. Contingent
Information on consequences
i.e., where, when, how or with whom must be specified.
17.identification
Teach toofuse
cues or preparatory
sub-goals
Information about approvalThis could include
contexts
in which the behaviour
18.specific
Follow
up prompts
Prompt intention formationbehaviours and/or
will be performed.
1.
2.
3.
4.
5. Specific goal setting
6. Graded tasks
7. Barrier identification
8. Behavioral contract
9. Review goals
10. Provide instruction
11. Model/ demonstrate
12. Prompt practice
13. Prompt monitoring
14. Provide feedback
19. Social comparison
20. Social support/ change
21. Role model
22. Prompt self talk
23. Relapse prevention
24. Stress management
The person is asked to keep a
25. Motivational
record
of specified interviewing
behaviour/s.
26.could
Timee.g.
management
This
take the form of a
diary or completing a
questionnaire about their
behaviour.
Further work ….
• Extended to 40 techniques reliably identified
with improved definitions
Michie et al, British Journal of Health Psychology, in press
• 71 techniques used in smoking cessation
interventions
Michie et al, Annals Behavioral Medicine, 2010
• 137 identified by
– consulting textbooks for training applied
psychologists in BC techniques
Michie et al, Applied Psychology: An International Review, 2008
• 42 in interventions to reduce excessive alcohol use
• Three year MRC grant to put taxonomy approach
onto a more scientific basis
– Expert coders needed!
Applications of taxonomy approach
1. Identifying active ingredients in interventions
– Meta-regression in evidence synthesis
•
•
Physical activity & healthy eating
Audit & Feedback
2. Investigating mechanisms of action (theoretical
mediation)
– The intervention “ProActive”
3. Designing interventions
– A classification based on comprehensive coverage,
coherence and a model of behaviour
Evidence syntheses of BC interventions
• Often find no clear patterns, inconsistent
results and small effects
• Synthesis depends on categorising complex,
multi-component interventions
• Categories often ad hoc
• Specifying content as BCTs allows
theoretically based categorisation & analysis
Identifying active ingredients in interventions
• Usual meta-analysis
– overall effect of heterogeneous interventions
• Technique-based meta-regression
– similar to traditional regression, except data at study
rather than individual level
– classify interventions into component BCTs
– meta-regression to investigate effects of
• individual techniques across interventions
• theoretically based combination of techniques
What BCTs are effective in interventions to increase
physical activity and healthy eating?
•
Inclusion criteria
–
–
–
–
•
•
6 electronic databases, 1990-2007
Intervention content analysed using
–
–
•
Interventions using behavioural &/or cognitive techniques
in adults
designs experimental or quasi-experimental
outcome measures objective or validated self-report
a reliable taxonomy of 26 techniques
a theoretically derived combination of techniques
Random effects meta-analysis and meta-regression
–
isolates unique contribution of specific techniques to
heterogeneity
Michie, Abraham, et al (2009) Effective techniques in healthy eating and physical
activity interventions: A meta-regression. Health Psychology, 28, 690-701
The interventions
• 84 interventions (n=28,838)
• Target behaviour
– Physical activity &/or Healthy eating
• Interventions ave. 6 techniques (range 1-14)
– Many different combinations
• Effect d=0.37, 95% CI 0.29-0.54
• Very heterogeneous effects (I2=79%)
– not explained by 10 moderators examined e.g.
• Setting, population, intervention characteristics, target behaviour
Results
• Only one technique, self-monitoring, had a
significant effect for both behaviours across
interventions
– d=0.57, 14.6% variance
• Next step
– Use psychological theory to predict combinations of
techniques that might be more effective
– Control Theory suggests how feedback may interact
with other techniques to change behaviour
Carver & Scheier, 1982
A Self-regulation (control) Theory: Carver & Scheier, 82
SELF-MONITORING/FEEDBACK
GOAL
GOALSETTING
Compare
behaviour
with standard
No
discrepancy –
goal reached
Discrepancy
noted
Act to reduce
discrepancy
ACTION-PLANNING
Environmental
influences
Disengage
from goal –
give up
Theoretical combination of techniques
• self-monitoring of behaviour
• Other core self regulatory processes:
–
–
–
–
setting goals
reviewing goals
specifying action plans
feedback on performance
Findings
• Interventions comprising self-monitoring with at
least one other “self-regulatory” techniques
(n=28)
compared with the other interventions (n=56)
• were twice as effective
• d=0.60 vs d=0.26
2. & 3. Applying theories of behaviour change
and matching BCTs to mechanisms of action
• Re-analysis of a Cochrane
review of professional
practice (Audit &
Feedback)
• ProActive intervention to
increase physical activity in
those at risk of Type 2
diabetes
Re-analysis of Cochrane review of Audit &
Feedback
Jamtvedt et al. Audit and feedback: effects on professional practice and
health care outcomes. Cochrane Database of Systematic Reviews 2006
• Intervention categorised as “intensive”,
“moderate” or “non-intensive”
What is “intensive”
Audit & Feedback?
• Intensive A&F
– (individual recipients) AND ((verbal format) OR (a
supervisor or senior colleague as the source))
AND (moderate or prolonged feedback)
• Non-intensive
– ((group feedback) NOT (from a supervisor or
senior colleague)) OR ((individual feedback) AND
(written format) AND (containing information about
costs or numbers of tests without personal
incentives))
• Moderate
– (any other combination of characteristics than
described in Intensive or Non-intensive group)
• No rationale for these categories in the published
review or when authors contacted
• Results:
–
–
–
–
118 RCTs with objective measures of performance
Variable effects, from 16% decrease to 70% increase
Small effect of “higher intensity” of A & F
No clear trend: Adjusted RR 1.55, 1.11 & 1.45 for high,
moderate and low intensity
• Limited use in informing evidence-based A&F
– ‘A&F will continue to be an unreliable approach … until
we learn how and when it works best’ (Foy et al, 2005)
Our re-analysis
•
•
Published reports usually inadequate for meaningful
data synthesis
Therefore, intervention details requested from authors
– 59 contacted, 44 responses,16 (27%) sent us additional
information (8 protocols)
•
•
Updated, 12 new RCTs, 69 excluded, 61 reporting 85
comparisons
Theory and evidence used to identify
– Intervention components
•
•
40 separate components coded, combined into BCTs
Theory-based hypotheses about effectiveness
Gardner, Whittington, McAteer, Eccles, Michie (2010) Using theory
to synthesise evidence from behaviour change interventions:
The example of audit and feedback. Social Science & Medicine
Coding and analysis
• Interventions coded for:
–
–
–
–
Goals (yes vs no)
Action plans (yes vs no)
Additional intervention BCTs (yes vs no)
Baseline compliance (continuous)
• Control conditions coded for:
– Additional intervention BCTs (yes vs no)
Michie, Prestwich, de Bruin M. (2010) Importance of the Nature of
Comparison Conditions for Testing Theory-Based Interventions:
Reply to Commentary. Health Psychology.
Self-regulation (control) Theory: Carver & Scheier, 82
FEEDBACK
GOAL
GOALSETTING
Compare
behaviour
with standard
No
discrepancy –
goal reached
Discrepancy
noted
Act to reduce
discrepancy
ACTION-PLANNING
Environmental
influences
Disengage
from goal
Theory-based hypotheses
• Feedback more effective when goal/target is set
• Most effective where goal/target and action plan
1. Feedback only
Effective
2. Feedback + goal
More effective
3. Feedback + goal + action plan
Most effective
Behaviour change techniques
Modes of delivery
• Non-intensive
• Feedback only
61 comparisons
• Feedback + goal
8 comparisons
• Feedback + goal + action
plan
3 comparisons
• Additional BCTs
– 73 interventions & 34
control arms
– ((group feedback) NOT (from a
supervisor or senior colleague))
OR ((individual feedback) AND
(written format) AND
(containing information about
costs or numbers of tests
without personal incentives))
• Moderate
– (any other combination of
characteristics than described
in Intensive or Non-intensive
group)
• Intensive A&F
– (individual recipients) AND
((verbal format) OR (a
supervisor or senior colleague
as the source)) AND (moderate
or prolonged feedback)
Results
• Meta-analysis:
– A&F effective: OR = 1.43 (95% CI = 1.28, 1.61)
– Moderate to strong heterogeneity (I2 = 61%)
• Meta-regression:
– Feedback vs Feedback + Goal &/or Action plan
• 61 vs 24 comparisons, adj. p = 1.0
• ?power
– Additional BCTs (intervention)
• p = .006
The intervention “ProActive”
Kinmonth et al, The Lancet, 2008
• Used BCT taxonomy approach to
– Assess fidelity of delivery
– Evaluate mechanism of action
• By linking intervention content to theory
The intervention and evaluation
• Based on psychological theory and evidence
• Specified in detailed protocols/manuals
• Delivered by trained professionals in 5 sessions
over 12 months
• Results of RCT
– Increased activity by equivalent of 20 minutes per day
– No difference between intervention and “control” groups
Implementation “add-on” study
• What worked?
• Assess implementation
Hardeman, Michie et al (2008) Fidelity of delivery of a physical activity
intervention: Predictors and consequences. Psychology and Health, 23, 11-24.
• How did it work?
• Link component techniques to theory
Michie, Hardeman et al (2008) Investigating Theoretical Explanations for
Behaviour Change: The Case Study of ProActive. Psychology and Health, 23,
25-39.
Intervention techniques
1.
2.
3.
4.
5.
6.
7.
Give information
Elicit questions
Summarise message
Set goals
Self-monitor
Build motivation
Action plans
8.
9.
10.
11.
12.
13.
14.
Theories
1.
2.
3.
4.
Theory of Planned Behaviour
Relapse Prevention Theory
Self-regulation Theory
Operant Learning Theory
Use prompts
Use rewards
Build support
Review goals
Build habits
Relapse prevention
Generalise skills
The implementation process
Theories of
behaviour change
Techniques
in manual
Delivery of
techniques by
professional
Participant
response to
intervention
Physical
activity
Method
• 27 participants selected to study in depth
• Intervention manual specified 208 behaviours
for delivering the 14 techniques
• Intervention sessions tape recorded &
transcribed
• All discussion in sessions relevant to
behaviour change was reliably coded into
techniques and theories
– Both of professionals and of participants
Question: How did the intervention work?
• 27 participants selected to study in depth
• Tape recorded and transcribed sessions
• All discussion in sessions relevant to
behaviour change was reliably coded into
techniques and theories
– Both of professionals and of participants
S
de
fin
e
G age
oa n
l s da
et
E Re ting
lic
it wa
qu rd
es s
t
A Mo ion
ct tiv s
io
n atio
pl
an n
In
n
S for ing
el
f-m ma
on tion
ito
r
S i ng
G up
H oal por
ab re t
it
v
fo iew
rm
R
el
ap P atio
se ro n
G pr mp
en ev t s
er en
al ti
is on
e
sk
ills
um
m
ar
is
e,
Percentage of techniques delivered by
professionals
%
45%
70
60
50
40
30
20
10
0
Variation in implementation
70
60
50
40
30
20
10
0
session session session session
4
3
2
1
Sessions: p<0.001 (Page test)
fac 1
fac 2
fac 3
fac 4
Facilitators: p<0.001
(Kruskal-Wallis test)
Consensus of at least 3 of 4 raters for:
Techniques
Theory
Build motivation
Theory of Planned
Behaviour
Give information
Set goals
Develop action plans
Self-monitoring
Review goals
Self-regulation Theory
Use rewards
Use prompts
Build support
Generalise skills
Build habits
Operant Learning Theory
Prepare for setbacks
Relapse Prevention Theory
How were techniques distributed over the
theories? (a) in protocol (b) delivered
35
30
25
20
%
protocol
15
10
5
0
delivered
Process linking theory and behaviour change
Theories of
behaviour change
Techniques
in manual
Delivery of
techniques by
professional
Participant
response to
intervention
Physical
activity
How was the intervention received by
participants?
Participants talk about behaviour change or maintenance was
reliably coded into 17 components of four theories e.g.
Example from
transcript
Theoretical
component
Theory
Thinking about
benefits of activity e.g.
losing weight
Attitude
Theory of Planned
Behaviour
Parking car further
away so has to walk
further
Action plan
Self-regulation
Theory
Asking partner to
remind him
Cue to action
Operant Learning
Theory
How was (a) professional (b) participant
talk about behaviour distributed over the theories?
50
45
40
35
30
% 25
20
15
10
5
0
professionals
participants
Which theories best accounted
for change?
Although Self-regulation theory is the
basis of the most commonly delivered
intervention techniques,
Operant learning theory may be a
better explanation for behaviour
change among participants
To develop more effective interventions …
We need to improve our scientific methods in the
following areas:
1. Specify intervention content in sufficient detail …
2. Apply theories of behaviour change to intervention
development and evaluation, and to evidence
syntheses
3. Match behaviour change techniques to mechanisms of
action …
4. Define the extent to which interventions, and
comparison conditions, use theory and evaluate how
this relates to effectiveness.
5. Develop a model of behaviour as a starting point for
systematic, theory-based intervention development.
4. Use of theory
• Many literature reviews conclude that behavioural
interventions based on theory are more effective than
those that are not
– E.g. Albarracin et al (2005), Downing et al (2006), Fisher & Fisher (2000),
Gehrman & Hovell (2003), Glanz & Bishop (2010), Jemmott & Jemmott (2000),
Kim et al (1997), Noar (2008), Wingood & DiClemente (1996)
• HOWEVER
– Researchers of reviewed studies generally state
rather than demonstrate a theoretical base for the
intervention
Need a method ….
•
•
of assessing the extent to which interventions
are based on theory
Theory Coding Scheme: Checklist of 19 items in
following categories:
– is a theory mentioned
– are relevant theoretical constructs targeted?
– is theory used to select recipients or tailor
interventions?
– are relevant theoretical constructs measured?
– is theory tested?
– is theory refined?
Michie S, Prestwich A. (2010) Are interventions theory-based?
Development of a Theory Coding Scheme. Health Psychology, 29,1-8.
Application of the framework: to address …
•
•
•
To what extent are interventions said to be theory based,
actually theory based?
Are theory-based interventions more effective than those
not explicitly based on theory?
Is intervention effect associated with
–
–
particular theories
particular use of theories
•
•
e.g. to select techniques, target participants
What is the association between theoretical base and
intervention content?
Test of Theory I:
meta-regression of smoking cessation counselling
• 3 Cochrane reviews
– Individual, group, telephone behavioral support
• Inadequate intervention descriptions
– Authors contacted
• 70 item taxonomy of BCTs for smoking cessation
interventions
• Theory Coding Scheme
Stavri, Beard, Whittington, Michie & West, 2010
Results: published intervention descriptions
• For 14
studies
where
protocols
available,
more BCTs
reported in
the protocols
(t(14)=3.63,
p<0.01)
7
6
5.9
5
Protocol
4
3
2.3
2
1
0
Number of BCTs
Published
description
Results: application of theory (n=92)
0
10
20
40
37
Is theory mentioned?
13
Are relevant theoretical constructs
targeted?
15
Is theory used to select recipients or
tailor interventions?
12
Are relevant theoretical constructs
measured?
6
Is theory tested?
Is theory refined?
30
0
Number of
studies
Theory use and effectiveness
• No association between theory use and
intervention effectiveness
• Types of theory
–
–
–
–
27 Transtheoretical Model
8 Relapse Prevention Model
1 Lazarus & Folkman’s model of stress
1 compared Relapse Prevention Model with Health
Belief Model
Results: BCTs associated with intervention
effectiveness
• Two BCTs were associated with intervention
effectiveness in psychological interventions
– Facilitate restructuring of social life (β=.56, R²=13.18%,
p=.02)
– Advise on/facilitate use of social support (β=.37,
R²=3.45% p=.02)
Test of Theory II: meta-analysis of internet
based interventions
Webb, Joseph, Yardley, & Michie (2010). Using the Internet
to promote health behaviour change: A systematic
review and meta-analysis of the impact of theoretical
basis, use of behavior change techniques, and mode of
delivery on efficacy. Journal of Medical Internet
Research, 12, e4.
Use of Theory
k
Q
95% CI
d+
Theory used to select recipients
3
2.84
0.15 to 0.52
0.33
Group of intervention techniques linked to group of
constructs
6
9.85
0.03 to 0.43
0.23
Theory used to select intervention techniques
37
191.40
0.13 to 0.29
0.21
Targeted construct mentioned as predictor of behaviour
18
60.07
0.11 to 0.31
0.21
Theory used to tailor intervention techniques to recipients
11
67.75
0.07 to 0.34
0.21
Theory or model of behaviour mentioned
30
161.33
0.11 to 0.28
0.19
At least one intervention technique is linked to theory
19
93.65
0.09 to 0.29
0.19
Intervention based on single theory
12
57.13
0.05 to 0.32
0.18
All constructs are linked to intervention techniques
10
47.70
-0.02 to 0.37
0.18
At least one construct is linked to an intervention technique
18
70.63
0.07 to 0.27
0.17
All intervention techniques are linked to theory
2
Use of theory associated with effect size
Effect size = -.07 + .03
0.30
Effect size (d)
0.20
0.10
0.00
0
1
2
3
4
5
-0.10
-0.20
Extent of use of theory: number of items
6
7
Currently applying Theory Coding Scheme to ….
• 146 papers reporting interventions to increase
physical activity and healthy eating
– 3 systematic reviews UCL, Leeds, Aberdeen
• Total sample size
– intervention groups 12,282
– control groups 12,248
• Watch this space …..
Prestwich, Whittington, Sniehotta & Michie, in preparation
To develop more effective interventions …
We need to improve our scientific methods in the following
areas:
1. Specify intervention content in sufficient detail in trial protocols and
published reports to allow accurate replication and evidence
syntheses that can identify “active ingredients” within interventions.
2. Apply theories of behaviour change to intervention development
and evaluation, and to evidence syntheses
• allows questions to be answered about not just “what worked” in
interventions but “how they worked”.
3. Match behaviour change techniques to mechanisms of action to
inform theory-based intervention development and evaluationbased theory development.
4. Define the extent to which interventions, and comparison
conditions, use theory and evaluate how this relates to
effectiveness.
5. Develop a model of behaviour as a starting point for systematic,
theory-based intervention development.
Designing interventions
• Start from an analysis of the nature of the
behaviour to be changed
• unless we understand the nature of the
behaviours that need to change, unlikely our
interventions will be maximally effective
Designing interventions ctd …
• Use a systematic approach to selecting from the
range of interventions and policies available
– Need a framework that meets criteria of
• comprehensive coverage,
• coherence
– categories mutually exclusive and same level of specificity
• linked to a model of behaviour
– Systematic review identified 18 existing frameworks,
none met all these criteria
Michie, van Straalen & West 2010
The Behaviour System: Behaviour emerges
from interactions between ….
Capability
Motivation
Opportunity
Psychological or physical ability to
enact the behaviour
Behaviour
Reflective and non-reflective
mechanisms that activate or inhibit
behaviour
Physical and social environment that
enables the behaviour
The Behaviour System: CMOB
Capability
Motivation
Opportunity
Capability, Motivation and Opportunity
must be present for a Behaviour to occur
Behaviour
The system is in dynamic
equilibrium and a change in
behaviour may require a
sustained change in one or more
of the other elements
The Behaviour Change Wheel: A system for
choosing interventions and policies
Behaviour source
Interventions:
activities
designed to
change
behaviours
Policies:
decisions
made by
authorities
concerning
interventions
Physical
Reflective
Non reflective
Social
Psychological
Physical
Motivation
Reflective
Nonreflective
Beliefs about what is good and bad,
conscious intentions and decisions as
per e.g. Theory of Planned Behaviour
Emotional responses, desires and
habits resulting from associative
learning and physiological states
Reflective-Impulsive Model, Strack & Deutsch, 2004
PRIME Theory of Motivation, West, 2006
The Behaviour Change Wheel
Behaviour source
Intervention
categories
Modelling
Policy
categories
Physical
Reflective
Non reflective
Social
Behaviour system
influenced by an
intervention system
which is enabled
and/or supported by
a policy system
Psychological
Physical
Intervention categories
Education
Imparting knowledge e.g. on health
risks
Persuasion
Using communication to induce belief
or knowledge
Incentivisation
Creating expectation of reward
Coercion
Creating expectation of punishment
or cost
Training
Imparting skills
Restriction
Reducing availability
Environmental
restructuring
Changing the physical context
Modelling
Providing an example for people to
aspire to
Enablement/
resources
Increasing means/reducing barriers
The Behaviour Change Wheel
Behaviour source
Intervention
categories
Environmental/
social planning
Policy
categories
Modelling
Physical
Reflective
Non reflective
Social
Psychological
Physical
Policy types
Communication/ marketing
Using print, electronic,
telephonic or broadcast media
Guidelines
Creating documents that
recommend or mandate practice
Fiscal
Using the tax system
Regulation
Establishing rules or principles
of behaviour or practice
Legislation
Making or changing laws
Environmental/ social
planning
Designing and/or controlling the
physical or social environment
Service provision
Delivering a service
Conclusions: If we are to ….
• most efficiently build evidence about BC
interventions
– need to specify intervention content and link to theory
• design more effective interventions to change
behaviour need to increase understanding of
– nature of behaviour
– range and nature of interventions/policies
– mechanisms of action
• and links between these
“He who loves practice without
theory is like the sailor who
boards ship without a rudder and
compass and never knows where
he may cast”
Leonardo Da Vinci, 1452-1519
More information from [email protected]