Measuring psychological development with the Rorschach.

The aim of this study was to develop and to provide an initial validation of a Rorschach index measuring developmental progress and growth. The Developmental Index (DI) was created in a 3-step, sequential strategy with adult and child data in which we (a) selected potential DI variables from quantitative research literature and from data available to us, (b) identified an optimal group of DI variables and created the DI equation using an independent nonpatient sample, and (c) provided an initial cross-validation of the DI using an independent clinical sample. Age and age rank categorization groups from normative data associated with the Wechsler intelligence scales (Wechsler, 2003, 2008) and contrasts between adults and children served as criteria for development. These samples include a large amount of data from a diverse international subject pool using the Comprehensive System of the Rorschach. Interim validity checks were undertaken to ensure the analytic strategy was sound. The DI includes 12 variables with individual weights determined by regression analysis. The initial independent cross-validation of the DI with a clinical sample revealed that it discriminated well between children and adults. Thus, initial support for this scale as a measure of psychological development across cultures and geography was established, but future research is needed. Clinical implications and specific research needs are presented.