[Development and psychometric testing of a patient questionnaire for medical rehabilitation (IRES-3)].
BACKGROUND
Re-analyses of extensive datasets as well as theoretical considerations have led to the conclusion that the patient questionnaire "Indicators of Rehabilitation Status" (IRES) should be revised in several respects. The new version IRES-3 was developed on the basis of a theoretical model of rehabilitation following the ICF (International Classification of Functioning, Disability and Health) as well as of elements of the earlier version IRES-2. In addition, we included the results of expert panels on the definition of treatment goals in medical rehabilitation.


METHODS
The IRES-3 was tested in 453 patients in rehabilitation clinics of seven diagnostic areas. To compare the IRES-3 with other generic instruments, the SF-36 and the HADS were employed at the same time. For purposes of cross-validation, an external sample could be used. The dimensional structure was tested in confirmatory factor analyses.


RESULTS
With rare exceptions, the tests showed good values for item difficulties, ceiling and floor effects, internal consistencies and test-retest-reliability. Convergent validity could be established for the IRES-3 when compared to relevant scales of the SF-36 and the HADS. Indices of sensitivity to change were comparable, if not somewhat superior to the effects on comparable scales of the SF-36. The assessment of the construct validity and the dimensional structure of the questionnaire led to the definition of eight dimensions which can be interpreted as somatic, emotional, functional, occupational, social, pain, coping, as well as health information and behaviour. The dimensional structure of the IRES-3 can be regarded as theoretically meaningful as well as empirically proven. STANDARDIZATION: For purposes of standardization, data were collected on a sample representative of the population aged 30-75 years in Germany. These data allow a norm-oriented interpretation of scales and dimensions of the IRES-3 for patients in rehabilitation.


CONCLUSIONS
The questionnaire is ready for application, including a computer programme for data entry and analysis.
Bührlen
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Fraunhofer-Institut für Systemtechnik und Innovationsforschung, Karlsruhe. b.buehrlen@isi.fraunhofer.de
Gerdes
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N
Jäckel
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D000203:Activities of Daily Living; D004185:Disability Evaluation; D005260:Female; D005858:Germany / Q000453:epidemiology; D006305:Health Status Indicators; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011594:Psychometrics / Q000379:methods*; D012046:Rehabilitation; D012680:Sensitivity and Specificity