Development and validation of the Two-Dimensional Social Interaction Scale (2DSIS).

The Two-Dimensional Social Interaction Scale (2DSIS) is a newly developed 20-item observer rating scale to assess four distinct categories of social interaction: active participate; active non-participate; passive participate; and passive non-participate. The scale was submitted to a validation procedure based on video recording of 59 dyadic social interactions between a confederate enacting one of the four types of social behaviours and a participant. The 2DSIS observer ratings on the participants were associated with meaningful differences in participants' social behaviour and their scores on the Social Adaptation Self-evaluation Scale. The 2DSIS observer ratings on the confederates were associated with participants' Post Encounter Scale scores. Factor analysis suggested that the four category ratings did exist in the two dimensions as proposed. The 2DSIS could be used in conjunction with conventional assessment tools to evaluate the social functioning of individuals.