How Effective are Behaviour Change Interventions

1
How Effective are Behaviour Change Interventions?

• Contents
• How do we measure effectiveness?
• How effective is medical therapy?
• How effective are psychological therapies?

2
Effect Size

• A standardized statistic to show the impact of
  treatments
• (Mean result for treatment group mean for
  controls) / standard deviation
• Interpretation
• An effect size of 0.5 represents a success rate
  of 65 in the treatment group, and 35 in the
  control group (success score above overall
  median)
• An effect size of 0.2 suggests 55 versus 45

3
Effect Sizes for Selected Medical Interventions
Mean Intervention Outcome effect
size Bypass graft surgery angina 0.80 ECT
depression 0.80 AZT for AIDS mortality 0.4
7 Drug treatment for hyperactivity behavior 0.47
to 0.96 Drug treatment for arthritis pain,
QoL 0.45 to 0.77 Dipyridamole angina 0.24 Ao
rtocoronary bypass surgery mortality 0.15 Drug
therapy for hypertension quality of life 0.11 to
0.28 Chemotherapy for breast cancer mortality 0.08
to 0.11
4
How Effective are Psychological Behavioral
Treatments?
mean Intervention studies effect
size General Psychotherapy 1231
0.79 Behaviour Modification 953
0.53 Family Marital Counselling 295
0.55 Treating Juvenile Delinquents 871
0.29 Meditation Relaxation 289
0.54 Biofeedback Relaxation 109
0.65 Smoking Cessation 125
0.55 Psychological Treatment for Pain 219
0.90