The German version of the Individualized Care Scale – assessing validity and reliability

AIM To assess validity and reliability of the German version of the Individualized Care Scale (ICS). BACKGROUND Individualized nursing care plays a pivotal role in establishing patient-centered care. To assess individualized nursing care and to compare it in different settings and countries, valid and reliable instruments are needed. No psychometric-tested instrument for comparing individualized nursing care with other countries is available in Germany. DESIGN Cross-sectional study. METHODS Data were collected between September 2013 and June 2014 from 606 patients in 20 wards in five hospitals across Germany. Unidimensionality of the ICS scales ICSA (patients' views on how individuality is supported through nursing interventions) and ICSB (patients' perceptions of individualized nursing care) was analyzed by confirmatory factor analysis. Internal consistency was assessed by calculating Cronbach's alpha. The Smoliner Scale (patients' perceptions of the decision-making process in nursing care) and results from participating hospitals' assessment of the nursing care delivery systems were used to assess known-groups validity and concurrent validity. RESULTS Fit indices of confirmatory factor analysis indicate unidimensionality of the ICSA (Comparative Fit Index: 0.92; Tucker-Lewis Index: 0.902; root mean square error of approximation: 0.09; standardized root mean square residual: 0.05) and the ICSB (Comparative Fit Index: 0.91; Tucker-Lewis Index: 0.89; root mean square error of approximation: 0.09; standardized root mean square residual: 0.05). Internal consistency using Cronbach's alpha was 0.95 (95% confidence interval: 0.94-0.95) for ICSA and 0.93 (95% confidence interval: 0.92-0.94) for the ICSB. Concurrent validity was established by a significant relationship between the Smoliner Scale and ICSA (r=0.66; P<0.01) and ICSB (r=0.72; P<0.01). Known-groups validity was approved by ICSA/ICSB score differences related to nursing care delivery systems and patients' perceptions of decision-making style. CONCLUSION The German version of the ICS is deemed a valid and reliable instrument for use in practice and research with hospitalized patients.