Cross-national research into the care of people with severe mental illnesses is hampered by a lack of standardised measures. The European Psychiatric Services: Inputs Linked to Outcome Domains and Needs (EPSILON) Study is a European Union funded project within the BIOMED-2 programme. The project aims to develop standardised instruments to facilitate future cross-national research.

To describe the aims, outcome measures, study sites and patient samples of the EPSILON Study.

See companion papers in this supplement.

Research on the comparison of mental health services has identified the need for internationally standardised and reliable measurements.

To describe the strategies adopted in the European Psychiatric Services: Inputs Linked to Outcome Domains and Needs (EPSILON) Study for the translation and cross-cultural adaptation of five European versions of the instruments.

A protocol was developed for translation of the outcome scales, describing each step in the translation procedure. Disputed items were discussed in focus groups, which faced seven tasks: a list of topics to be discussed; choosing where the group should meet; composition of participants; conducting the group; data collection; data completion afterwards; reporting results.

Modifications made to instruments were: changes in the instrument structure, contents and concepts; adjustments to the instrument structure; and modifications to the instrument manual.

Use of focus groups is an adequate method to apply if concepts, constructs and translation issues are to be addressed; otherwise, less time-consuming methods should be considered.

The European Psychiatric Services: Inputs Linked to Outcome Domains and Needs (EPSILON) Study aims to produce standardised versions in five European languages of instruments measuring needs for care, family or caregiving burden, satisfaction with services, quality of life, and sociodemographic and service receipt.

To describe background, rationale and design of the reliability study, focusing on reliable instruments, reliability testing theory, a general reliability testing procedure and sample size requirements.

A strict protocol was developed, consisting of definitions of the specific reliability measures used, the statistical methods used to assess these reliability coefficients, the development of statistical programmes to make inter-centre reliability comparisons, criteria for good reliability, and a general format for the reliability analysis.

The reliability analyses are based on classical test theory. Reliability measures used are Cronbach's α, Cohen's κ and the intraclass correlation coefficient. Intersite comparisons were extended with a comparison of the standard error of measurement. Criteria for good reliability may need to be adapted for this type of study. The consequences of low reliability, and reliability differing between sites, must be considered before pooling data.

In international research on the consequences of psychiatric illnesses for relatives of patients, the need for an internationally standardised measure has been identified.

To test the internal consistency and the test-retest reliability of the Involvement Evaluation Questionnaire (IEQ) in five European countries.

The IEQ was administered twice to a sample of relatives or friends of patients with an ICD-10 diagnosis of schizophrenia. Reliability was tested using Cronbach's α, intraclass correlation coefficients and standard error of measurement. Reliability estimates were tested between sites.

Test sample sizes ranged from 30 to 90 across sites, and retest sample sizes ranged from 21 to 77. Cronbach's α values of IEQ sub-scales and sumscore were substantial at most sites; but at two, α values were moderate. Intraclass correlation coefficients were substantial to high at all sites. The standard errors of measurement differed across sites, indicating differences in performance.

The reliability of the IEQ in five languages varies across sites, but is sufficiently high in at least four out of five.

Cross-cultural comparison of mental health service utilisation and costs is complicated by the heterogeneity of service systems. For data to be locally meaningful yet internationally comparable, a carefully constructed approach to its collection is required.

To develop a research method and instrument for the collection of data on the service utilisation and related characteristics of people with mental disorders, as the basis for calculating the costs of care.

Various approaches to the collection of service use data and key stages of instrument development were identified in order to select the most appropriate methods.

Based on previous work, and following translation and cross-cultural validation, an instrument was developed: the Client Socio-Demographic and Service Receipt Inventory – European Version (CSSRI–EU). This was subsequently administered to 404 people with schizophrenia across five countries.

The CSSRI – EU provides a standardised yet adaptable method for collating service receipt and associated data alongside assessment of patient outcomes.

The five-country European Psychiatric Services: Inputs Linked to Outcome Domains and Needs (EPSILON) Study aimed to develop standardised and reliable outcome instruments for people with schizophrenia. This paper reports reliability findings for the Camberwell Assessment of Need – European Version (CAN-EU).

The CAN – EU was administered in each country, at two points in time to assess test – retest reliability, and was rated by two interviewers at the first administration. Cronbach's α, test–retest reliability and interrater reliability were compared between the five sites. Reliability coefficients and standard errors of measurement for summary scores were estimated.

Sites varied in levels and spread of needs. Alphas were 0.48, 0.58 and 0.64 for total, met and unmet needs respectively. Test–retest reliability estimates, pooled over sites, were 0.85 for the total needs, 0.69 for met needs and 0.78 for unmet needs. Pooled estimates for interrater reliability were higher, at 0.94, 0.85 and 0.79 for total, met and unmet needs respectively. There were statistically significant differences in interrater reliability between sites.

The results confirm the feasibility of using CAN–EU across sites in Europe and its psychometric adequacy.

Satisfaction with mental health services is an important quality and outcome variable. The Verona Service Satisfaction Scale (VSSS) is a well-established method for measuiring service satisfaction.

To report the development and reliability study of the European Version of the VSSS (VSSS–EU).

A sample of people with schizophrenia on the case-load of local mental health services in the five European participating countries was assessed. The VSSS–EU was administered at one site in each country at two points in time. Internal consistency and test–retest reliability were assessed and compared between the five sites.

The α coefficient for the VSSS–EU total score in the pooled sample was 0.96 (95% CI 0.94–0.97) and ranged from 0.92 (95% CI 0.60–1.00) to 0.96 (95% CI 0.93–0.98) across the sites. Test–retest reliability for VSSS–EU total score, pooled over sites, was 0.82 (95% CI 0.78–0.85) and ranged from 0.73 (95% CI 0.6–0.86) to 0.93 (95% CI 0.89–0.97) across the sites.

VSSS–EU is a reliable instrument for measuring service satisfaction in people with schizophrenia, for use in comparative cross-national research projects and in routine clinical practice in mental health services across Europe.

This paper, part of the European Psychiatric Services: Inputs Linked to Outcome Domains and Needs (EPSILON) Study, reports the development, reliability and internal consistency of the Lancashire Quality of Life Profile – European Version (LQoLP–EU) in a representative sample of people with schizophrenia from five European sites.

The LQoLP–EU was administered to a total sample of 404 patients to check its internal consistency, and a sub-sample of 294 patients was interviewed a second time within 7–15 days to verify its test–retest reliability.

Internal consistency of the total domains, perceived QoL scale (Life Satisfaction Scale, LSS) was good at 0.87. Of the nine subjective QoL domains Work and Leisure showed the lowest internal consistency (0.30 and 0.56 respectively), the values of the remaining sub-scales ranging between 0.62 and 0.88. The pooled ICC score for LSS was 0.82, and for the nine subjective QoL domain sub-scales it ranged from 0.61 (Safety) to 0.75 (Living Situation). There were significant differences between the sites in α and ICCs for sub-scales, but not for the LSS.

The LQoLP-EU has good internal consistency and reliability in the five European centres.