The Overt Agitation Severity Scale for the objective rating of agitation.

Two studies tested the reliability and validity of the Overt Agitation Severity Scale (OASS), a new instrument developed to define and objectively rate the severity of agitated behavior. The authors postulate that agitation should be conceptualized as vocal and motor behaviors on a continuum of expressions that extends from anxiety to aggression. Content validity through expert agreement was achieved in the development of test construction over a 2-year period. Results of two pilot studies (n = 25 and n = 14 subjects) established the reliability and validity of the OASS to measure agitation severity. The OASS differs from other agitation scales in that it confines its rating exclusively to observable behavioral manifestations of agitation.