The Extended Staff Observation Aggression Scale (SOAS-E): development, presentation and evaluation.

The Staff Observation Aggression Scale (SOAS) was developed as a scale for reporting aggressive incidents involving psychiatric in-patients. The SOAS -- Extended Version (SOAS-E) has the same aim, but has additional categories and subcategories. The SOAS-E clearly distinguishes between violent and non-violent aggressive behaviour and characterizes in more detail the associated situation. However, the main contribution of the SOAS-E is the introduction of a category of 'warning signals' that precede the releasing 'provocation factor' as a separate and primary aspect of the cyclus of aggressive incidents. The development of the SOAS-E is described, and the testing and inter-rater reliability of the warning signals category are examined. Compared to the SOAS, the additional categories of the SOAS-E are found to increase the scope for a detailed characterization of aggressive behaviour in psychiatric wards.