A reliability study of psychiatric diagnosis in childhood and adolescence.

The reliability study on the G.A.P. classification by 20 psychiatrists has demonstrated a high interindividual and intraindividual consistency. This diagnostic consistency is equal to the findings of any high agreement study in adult psychiatry and comparable with diagnostic error reported in other medical specialities. Garland (1959) proposed that all forms of clinical practice have a measurable degree of diagnostic error and if all branches of medicine could be tested this phenomenon would probably be quite universal. The New South Wales study on the G.A.P. classification has confirmed that child psychiatry is no exception to this rule.