Background and purpose: The purpose of this study was to test the reliability and validity of the conceptual model of critical care nursing using the Nursing Activities Score (NAS) for intensive care unit (ICU) patients.
Methods: An observational study conducted in 2011 using the NAS scores of 219 patients in Norway. The inter-rater reliability (IRR) was tested by parallel classifications. The validity was explored by an exploratory factor analysis (EFA) and a confirmatory factor analysis (CFA) as the measurement models in the structural equation model.
Results: Within the paired ratings the Spearman's correlation coefficient was 0.39. The EFA results explained 77% of the variance with six factors. The reduced CFA model resulted in a three-factor model: relationship, prevention and treatment.
Conclusion: The findings supported the IRR and construct validity of the conceptual model of the NAS.