This document discusses motivational interviewing (MI) as a complex intervention and proposes applying a complex interventions perspective to better understand MI. It suggests that thinking of MI as a complex intervention and using systematic reviews and studies of heterogeneity can help address the large variability seen in MI's effectiveness between studies. The document provides some examples of meta-analyses looking at whether certain factors like medical setting, provider training, or measurement type moderate MI outcomes. It argues that more systematic reviews and methods are needed to better understand MI when implemented in real-world settings.

1. Motivational interviewing
as a complex intervention
Jim McCambridge
ICMI-3 in Venice, June 19th 2012
Improving health worldwide
www.lshtm.ac.uk

3. Outline
1. Introduce complex interventions (CI) perspective and apply it to
MI
2. Propose value of systematic reviews & studies of heterogeneity
- Play with ideas of simplicity and complexity
(+ a little data)

4. 2 UK MRC documents
• http://www.mrc.ac.uk/Utilities/Documentrec
ord/index.htm?d=MRC003372
• http://www.mrc.ac.uk/Ourresearch/Research
Initiatives/Methodologyresearch/documents/
index.htm

5. Definition
CIs comprise “a number of separate
elements which seem essential to the
proper functioning of the
interventions although the ‘active
ingredient’ of the intervention that is
effective is difficult to specify”

6. An alternative perspective
• Alan Shiell & Penelope Hawe
• Interventions conceptualised as events in complex
systems.....which are adaptive and self-regulating

7. How is a CI different from a
simple one?
• Pragmatic distinction made according to what we
want to find out
– Aspirin, can be conceptualised as either
– MI, ditto

8. Two suggestions
• It may be useful to think of MI as a CI
• Simplicity is often the best strategy for dealing with
complexity

11. Shepperd et al. recommendations
• Components, typologies of structural characteristics for mechanisms
studies
• Qualitative data
• Quantitative data syntheses in systematic reviews
• Narrative syntheses in systematic reviews

12. Beyond effectiveness
estimates
• Much unexplained variability in effectiveness of MI –
effect sizes “disturbingly erratic”....Pandora’s box...
• This will get much worse as large effectiveness trials,
including more frequent null findings accumulate
• Why do there appear to be differences in the
effectiveness of MI?

13. Does medical setting
moderate outcome? No.
O.R. K
Hospital 1.15* 15
Physician office / clinic 1.37* 15
Emergency Department 1.40* 5
HIV Clinic with medical center 1.20* 3
Home Health 1.52* 2
Dentist 1.85* 1
Physical Therapy 1.92* 1

14. Does provider training
moderate outcome? No.
O.R. K
Mental health professional 1.43* 12
Mixture 1.14* 11
Nurse 1.27* 7
Dietician 1.32* 3
Physician 1.21* 2

15. Does measurement type
moderate outcomes? Yes.
O.R. N
Self-report 1.67* 226
Professionally kept records 1.48* 30
Biophysical indicators 1.22* 84
Self-report > Biophysical
Records > Biophysical
Note: N = number of effect sizes, not number of studies.

16. Did comparison group
moderate outcome? No,
suggesting M.I. is at least as
good as other programs
O.R. K
Waitlist 1.91* 7
Information only 1.54* 16
Treatment as usual 1.51* 31

17. Meta analysis is a statistical technique – does not require
consideration of biases
Systematic review is a research design that provides a
strategy for dealing with complexity to make valid
inferences
We need more systematic reviews of MI

18. Beyond systematic reviews
1. Meta-epidemiological methods for resolving differences in
meta-analytic findings
2. Narrative methods also have the capacity to be sensitive
to inference – reviews of reviews
3. Both have capacity to generate new research questions

20. Take home messages
• Getting to grips with complexity across studies as well
as within them helps better understanding MI
• We can do much more with what’s already been done
• Answers relatively easy to get, asking the right
research questions and choosing the right designs
harder
• Keep it all simple as far as possible!

22. Acknowledgements
• Long term funding by the Wellcome Trust
• Many many colleagues and friends for helping with
development of ideas
• Brad Lundahl and Jean Bernard Daeppen
• Miller & Rollnick for presenting what is complex simply