The reliability and validity of the Chinese version of the Modified Overt Aggression Scale

Objective. Instruments to assess aggressive behaviors in the psychiatric ward are crucial for monitoring risky behaviors. The purpose of this study was to assess the validity and reliability of the Chinese version of the Modified Overt Aggression Scale (MOAS). Methods. We translated the English version of MOAS into Chinese. We interviewed and trained two volunteers to act as agitated patients in the seclusion room. One senior psychiatrist, experienced in using the MOAS, directed scenarios of different aggressive intensity and established the standard scores. The validity was assessed by comparing the other raters' scores with those of the director's. Inter-rater reliability was also assessed. Results. Inter-rater reliability, based on Intra-class correlation coefficient (ICC=0.94, P<0.001) and Kendall's W coefficient of concordance (W=0.83, P= 0.001), was high. The validity was assessed by the Mann-Whitney test. The results showed that the raters adequately differentiated (z=- 2.89, P= 0.002) between the above-average and below-average scores of the MOAS. Conclusion. The Chinese version of the MOAS has modest psychometric properties. The model, which used trained volunteers acting as patients and compared their scores with those of the director, may be used in further studies for developing psychometric instruments to assess abrupt behaviors.