A PRECEDING paper described the development and design of a Short Clinical Rating Scale (SCRS) consisting of 13 items. The scale was designed to be used in an acute treatment and research unit and to meet requirements which are not met by other existing scales: ie, it should be easily and rapidly rateable by all nursing personnel on an hourly, daily, or weekly basis; provide objective and clinically relevant measurements of the major components of the more severe psychiatric syndromes; be useable longitudinally without further complex data processing; and be viewed by the raters as being relevant to their daily work.¹ Since the introduction of any new rating scale always raises the question of the reliability and validity of the measurements and since the behavioral data obtained from the use of this scale has been used in several collaborating research projects, this paper describes a series of studies assessing the