Psychometric evaluation of Chinese version of Violence Scale for objective rating among inpatients with schizophrenia

The psychometric properties of the Chinese version of Violence Scale in clinical service setting were examined. Psychiatric inpatient's aggressive act is a significant clinical issue in psychiatric service. A useful objective rating scale for prospective study and clinical application was mandatory. A prospective panel study. The Chinese version of Violence Scale developed from Morrison's Violence Scale. Sampled patients (n = 107) with schizophrenia spectrum, fulfilling the DSM-IV criteria, were recruited consecutively in a psychiatric acute ward of a university hospital over a period of one-year. The patients' counts of the aggressive acts measured by the Chinese version of Violence Scale occurred in the past one-month prior to admission and in the prospective initial-week after admission were collected during their hospitalisation. The prospective occurrence was observed daily and summed at a fixed weekly point. The internal consistency, content validity and predictive validity of the Chinese version of Violence Scale were examined. Also, a confirmatory factors analysis by LISREL was conducted to examine its measurement structure. The Chinese version of Violence Scale follows a Poisson distribution of a fair quality (Cronbach's alpha = 0.67). The Chinese version of Violence Scale with panel's content validity has good predictive validity (r = 0.51, p < 0.001). Those correlated to one latent variable with six items, which constructs a core meaning of 'threatening aggression toward others'. This panel study provides evidence for fair reliability and satisfactory validity of the Chinese version of Violence Scale. Internal consistency of the Chinese version of Violence Scale is limited and it may be because of the time-varying characteristic and hierarchical pattern of the behaviour items. To further investigate the count scale of the Chinese version of Violence Scale follows a Poisson distribution, the over-dispersion and weighting issues of aggressive acts were suggested to approach. This study highlights the measurement issues and implications of the Chinese version of Violence Scale for objectively rating psychiatric patients' aggressive acts to further develop fitted nursing care and prevention program.