Caregiving in schizophrenia: development, internal consistency and reliability of the Involvement Evaluation Questionnaire - European Version - EPSILON Study 4

Background In international research on the consequences of psychiatric ill nesses for relatives of patients, the need for an internationally standardi sed measure has been identified. Aims To test the internal consistency and the test-retest reliability of th e Involvement Evaluation Questionnaire (IEQ) in five European countries. Method The IEQ was administered twice to a sample of relatives or friends o f patients with an ICD-10 diagnosis of schizophrenia. Reliability was teste d using Cronbach's alpha, intraclass correlation coefficients and standard error of measurement. Reliability estimates were tested between sites. Results Test sample sizes ranged from 30 to 90 across sites, and retest sam ple sizes ranged from 21 to 77 Cronbach's a Values of IEQ sub-scales and su mscore were substantial at most sites; but at two. a values were moderate. Intraclass correlation coefficients were substantial to high at all sites. The standard errors of measurement differed across sites, indicating differ ences in performance. Conclusion The reliability of the IEQ in five languages varies across sites , but is sufficiently high in at least four out of five. Declaration of interest No conflict of interest. Funding detailed in Acknow ledgements.