Psychometric Properties of the Persian Version of the Staff Observation Aggression Scale-Revised (SOAS-R) in Psychiatric Patients

Introduction: In psychiatric settings, aggressive events frequently occur during therapy. The use of a proper standard scale to register aggression can facilitate the assessment and control of aggression and help reduce its frequency and severity. The aim of this study is to evaluate the validity and reliability of the Staff Observation Aggression Scale-Revised (SOAS-R). Methods: This psychometric study of the scale was conducted to determine the validity and reliability of the SOAS-R. The validation of the scale was assessed on the basis of 319 aggressive events in the psychiatric wards of the Baqiyatallah and Roozbeh hospitals. Convenience sampling was used for subject selection. Psychometric properties of SOAS-R were studied in two stages. First, the standard scale was translated according to the International Quality of Life Assessment (IQOLA) translation methodology. The face validity, content, and construct validity of the translated version were then determined. The construct validity of the scale was assessed by comparing the known groups. Results: The internal consistency of the whole scale was 0.99. The intra-class correlation coefficients (ICC) were 0.85-0.99 while kappa coefficient was 0.43 to 0.65 for different aspects of the SOAS-R. The validity of the scale was concurrently assessed by using the Visual Analogue Scale (VAS), with a Spearman-Brown correlation coefficient of 0.90. Conclusion: These results showed a favourable validity and reliability for the Persian version of the SOAS-R for the assessment of aggressive behaviour in psychiatric patients.