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Broad Outcome Measures May Underestimate Effectiveness: An Instrument Comparison Study
William Lee1, Lynne Jones2, Robert Goodman3
1Academic Dept of Psychological Medicine, GKT School of Medicine & Institute of Psychiatry, Weston Education Centre, Cutcombe Road, London SE5 9RJ, UK.
Background:
Outcome measures are routinely used in child and adolescent mental health services to demonstrate the effectiveness or otherwise of interventions.
Methods:
We followed up a consecutive sample from a large teaching hospital's Obsessive Compulsive Disorder (OCD) service for young people, comparing improvements using instruments of differing broadness.
Results:
The effect size of improvement decreased as the breadth of the questionnaire increased.
Conclusion:
Specialist clinics are recommended to use two questionnaires: a broad one to facilitate comparability with other clinics, and a narrow one to maximise power to detect significant changes.
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