Thesis Open Access
This paper aims to develop an instrument for measuring pictorial expression. The approach of test construction is theory-based and empirically supported. The definition of the theoretical construct is based on art historical and art therapeutic theories of image analysis. It defines pictorial expression in seven content areas (representation, color, shape, space, motion, composition, expression), which are compounded to the overall construct. For an empirical test nine two-dimensional pictorial artworks by non-professionals are selected and rated by experts (N = 12) on all items via an online study. All experts are art therapists. Starting with an itempool of 113 items, all those items with non-satisfying psychometric characteristics are excluded. This decision is based on values obtained by statistical analyses of item difficulty, inter-rater reliability, differentiation capability and inter-item correlations. The final version of RizbA includes 26 items. Its inter-rater reliability is .525 and its ability for differentiation between pictorial works is .897.