Measuring art: Methodical development of a quantitative rating instrument measuring pictorial expression (RizbA)

Abstract

Art therapy theory assumes that art work is related to differential constructs of the artist. Empirically, this hypothesis has not been established because findings based on quantitative methods are rare. The Rating Instrument for two-dimensional Pictorial Work (RizbA) is designed to address this issue. The construct − pictorial expression − is theoretically defined by seven content areas: representation, color, shape, space, motion, composition, expression. In combination these create the overall test construct. The test development is based on art historical and art therapeutic theories, and the findings are supported empirically. Two online studies were conducted using a sample of nine pictures. These were rated by experts (n1=12, n2=8). In the first study, based on psychometric characteristics, an item pool of 113 items was examined and a preliminary test version developed. The second study examined quality criteria of the preliminary version. For both studies, factor analyses were computed.The preliminary version includes 26 items. Its ability for differentiation between pictorial works ranges between .897 (T1) and .766 (T2), its inter-rater reliability between .525 (T1) and .917 (T2). Test-retest reliability is .919. PCA suggests a four-factors solution, which in large part is consistent across studies. As a reliable measurement RizbA opens new perspectives in fundamental art therapeutic and psychological research.